Ultracold polar molecular gases, promising strong electric dipole-dipole interaction and a long lifetime in a 3D optical lattice, are good candidates for investigating many-body physics with long-range interactions. In this talk, I will report the progress of ultracold 23Na40K molecule experiments in Munich. We successfully produced rovibrational ground state 23Na40K molecules by a detuned STIRAP. We observe a two-body collisional loss of the ground state 23Na40K molecule although the collision is chemical stable, which is probably due to the sticky collision between molecules. I will also discuss the preliminary results of microwave manipulation of rotational states of 23Na40K molecule in a 1D optical lattice. These results pave the way to make degenerate polar molecular gas in optical lattice for quantum simulation.