Abstract: Nonadaptive coordinate transformations are applied to the basic equations for the simulation of thermal blooming of focused high –power beams propagation through the atmosphere in the report. The results show that the accuracy and speed of the computation can be improved efficiently. But it is difficult to calculate the field near the focal plane because of the defocusing of the thermal blooming. A modified nonadaptive changes are presented in the paper which overcome the disadvantage of the old nonadaptive changes, and has proved to be more efficient in the improvement of accuracy and speed of computation, and reduction of computer’s memory.