Hi Lei, libmed1, a library gmsh needs, depends on libhdf5-openmpi-6, whereas woo depends on libhdf5-7 (without openmpi) and these two flavors conflict with each other. I am now on travels without access to a proper machine, so I cannot help much more.
This situation means there is a problem with packaging of either woo or of libmed1. My guess is the second one, but I'd have to ask debian maintainers what is the way to depend on HDF5 in a proper way.
A way around this can be to compile woo from the source (then the hdf5 flavor installed will be used, I suppose), or (sorry for lack of better solution) avoid using both simulatenously at the same machine.
In a few weeks, I will look at a proper solution, the issue will be tracked under https://github.com/woodem/woo/issues/27