Advanced engineering structures require dissimilar metal jointing. Laser welding has such merits as high energy density, high depth-to-width ratio, narrow heat-affected zone and limited shape-deformation. Therefore, it becomes one of the effective approaches for jointing dissimilar metal combination. The procedure of laser welding for dissimilar metal is very complex.There are some key issues about laser welding mechanism, for instance, thermal-physical material properties, melt pool dynamics, melt-condensation mechanism, formation of welding defects and residual stress. The progress and present research of experimental and numerical simulation about these issues are discussed. On this basis, some problems of laser welding of dissimilar metal materials are put forward.