Abstract: Two kinds of computational metheds in variable time steps are put forward,on the basis of explicit and complete square conservative difference scheme,which can make numerical comPutation more efficiently.The first one is the artificial method in adjusting to the time step,which can be realized by controling the variation of operator energy in equation artificially.The automatic method in adjusting to the time step can give out whether the stability of difference scheme is good or not by numerical tests,and can be proved with the function that can synthetically judge the effect of difference scheme by the combined application with the method of Taylor expansion,and the splitting method.At last,some reasonable conclusions habe been drawn out.