Hi, I think to read the xdmf, you can refer to this post
https://fenicsproject.org/qa/11348/read-in-mesh-and-functins-from-xdmf-file/
run the following
from dolfin import *
mesh = Mesh()
filename = “mesh.xdmf”
f = XDMFFile(mpi_comm_world(), filename)
f.read(mesh, True)
plot(mesh)