[en] To solve the multi-dimensional transient neutron diffusion equations, improved quasi-static Green's function method (IQS/NGFM) is adopted to deal with the temporal problem, which will increase the time step as long as possible so as to decrease the number of times of spatial calculation. The time step of IQS/NGFM can be increased to 5∼10 times longer than that of full implicit differential method. In spatial calculation, the theory of NGFM is used to get the distribution of shape function, with coarse meshes which can be nearly 20 times larger than that of traditional finite differential method. So the IQS/NGFM is considered as an efficient kinetic method