Oh,This is my fault.I type the wrong format(now,I know the right format should be "@name==*" , forgive my stupidity.) in the Partition Attribute,so It give me a"Houdini Console".
Follow the Old School 's method,It is working!thanks to you,Master Old School.
But,I encountered a new problem that if I use two (or more) PRIMITIVE geometry(Primitive Type:Primitive)merge together.and then add a connectivity SOP and a Attribute Create SOP,type the attribute in the Alembic Partition Attribute,I can get the right pieces objects.But if I use two(or more)POLYGON geometry(Primitive Type:Polygon)merge together,and then ... ... ,it doesn't work.
In the convert SOP ,it haven't a function to convert a polygon to a primitive.and I don't know how to add a "polygon attribute" like a primitive attribute.
If you can't understand my bad English.Please download my file.I think it will help you understand my problem.