Numerical simulation of radiation transfer equations arises in many applications, including astrophysics, inertial confinement fusion, optical molecular imaging, shielding, and so on. The positivity-preserving and conservation-preserving properties are two important and challenging issues for the numerical solution of this kind of equations. In this talk, I will introduce our recent work on high order positivity-preserving and conservative discontinuous Galerkin (DG) schemes solving steady and unsteady radiation transfer equations. The properties such as positivity-preserving and high order accuracy are proven rigorously. One- and two-dimensional numerical results are provided to verify the designed characteristics of our schemes.