I found the AddPorts() Method，Sorry I missed it before.

from typing import Optional
import c4d
import maxon

doc: c4d.documents.BaseDocument  # The active document
op: Optional[c4d.BaseObject]  # The active object, None if unselected

def main() -> None:
    material = doc.GetActiveMaterial()
    nodeMaterial = material.GetNodeMaterialReference()
    graph: maxon.GraphModelInterface = nodeMaterial.GetGraph(c4d.GetActiveNodeSpaceId())
    
    with graph.BeginTransaction() as transaction:
        
        layered_node = graph.AddChild(maxon.Id(),"com.chaos.vray_node.texlayeredmax")
        layers = layered_node.GetInputs().FindChild("com.chaos.vray_node.texlayeredmax.texture_layers") #The Layers portbundle
        layers.AddPorts(2, 1) #Add layers

        transaction.Commit()
    
    
    #Layer in Layers portbundle
    layers_list = []
    layers.GetChildren(layers_list,maxon.NODE_KIND.INPORT)
    
    #Textureports and BlendMode_ports in Layers portbundle
    layers_texport_list = [tport for port in layers_list if (tport := port.FindChild("com.chaos.vray.portbundle.texture_layer.texture"))]
    layers_mode_list = [mport for port in layers_list if (mport := port.FindChild("com.chaos.vray.portbundle.texture_layer.blend_mode"))]
    
    
    print(layered_node)
    print(layers)
    print(layers_list)
    print(layers_texport_list)
    print(layers_mode_list)


if __name__ == '__main__':
    main()

I found the AddPorts() Method，Sorry I missed it before.

from typing import Optional
import c4d
import maxon

doc: c4d.documents.BaseDocument  # The active document
op: Optional[c4d.BaseObject]  # The active object, None if unselected

def main() -> None:
    material = doc.GetActiveMaterial()
    nodeMaterial = material.GetNodeMaterialReference()
    graph: maxon.GraphModelInterface = nodeMaterial.GetGraph(c4d.GetActiveNodeSpaceId())
    
    with graph.BeginTransaction() as transaction:
        
        layered_node = graph.AddChild(maxon.Id(),"com.chaos.vray_node.texlayeredmax")
        layers = layered_node.GetInputs().FindChild("com.chaos.vray_node.texlayeredmax.texture_layers") #The Layers portbundle
        layers.AddPorts(2, 1) #Add layers

        transaction.Commit()
    
    
    #Layer in Layers portbundle
    layers_list = []
    layers.GetChildren(layers_list,maxon.NODE_KIND.INPORT)
    
    #Textureports and BlendMode_ports in Layers portbundle
    layers_texport_list = [tport for port in layers_list if (tport := port.FindChild("com.chaos.vray.portbundle.texture_layer.texture"))]
    layers_mode_list = [mport for port in layers_list if (mport := port.FindChild("com.chaos.vray.portbundle.texture_layer.blend_mode"))]
    
    
    print(layered_node)
    print(layers)
    print(layers_list)
    print(layers_texport_list)
    print(layers_mode_list)


if __name__ == '__main__':
    main()

Hi! @i_mazlov ,
Thanks for your reply，I will take a look at the Forum and Support Guidelines.
About the question
Is there any other way to 'add layer' to the node other than ‘’press‘’ the button？

As shown in the following screenshot.

It's Vray NodeMaterial in the picture,but I found the same structure in scene_root Node and the C4D NodeMaterial.
I had tried GraphNode.SetValue and GraphNode.SetDefaultValue.but I don't know how to set the "value" because it's a Array<Tuple<Id, DataDictionary>> Type.
I did write some codes and I know that they are wrong.But I dont know how to correct it.

from typing import Optional
import c4d
import maxon

doc: c4d.documents.BaseDocument  # The active document
op: Optional[c4d.BaseObject]  # The active object, None if unselected




def main() -> None:
    material = doc.GetActiveMaterial()
    nodeMaterial = material.GetNodeMaterialReference()
    graph: maxon.GraphModelInterface = nodeMaterial.GetGraph(c4d.GetActiveNodeSpaceId())

    layered_list = []
    maxon.GraphModelHelper.FindNodesById(graph,"com.chaos.vray_node.texlayeredmax.texture_layers",maxon.NODE_KIND.INPORT, maxon.PORT_DIR.INPUT, False, layered_list)
    layered_node = layered_list[0]


    
    with graph.BeginTransaction() as transaction:
        data_dict:maxon.DataDictionary = {}
        key = "net.maxon.node.attribute.insertindex"
        value = 1
        data_dict[key] = value
        tuple_l = ["_0",data_dict]
        array = {tuple_l}

        layered_node.SetDefaultValue(array)
        
        transaction.Commit()



    print(tuple_l)


if __name__ == '__main__':
    main()

thanks.