With the development of the UHV project in China, the connectivity of large power grids has been strengthened, and the problem of exceeding the standard of short circuit current is becoming more and more serious. PSASP and PSDE-SCCP are two main softwares for short-circuit current calculation at present in China. However, there are great differences between these two softwares’ computing result, affecting power grid planning and decision-making. This paper analyzes the main influence of the short circuit, and compares two kinds of program based on the short-circuit current calculation results under the different ways according to the existing short-circuit current calculation standards in China. Considering the actual operating conditions in the power grid, under the same conditions, it compares and analyzes the differences in the short-circuit current calculations for different voltage levels and load model types for these two programs. According to the results of the studies, the set standard of the short circuit current calculation based on the two program softwares is apply to the different load models under the specific gravity of the actual power grid. Combined with the actual power grid, the calculation of short-circuit current in the planning for the construction of power grid provides reasonable reference basis. This work is supported by National Natural Science Foundation of China (No. 51467006).