Abstract: As an index to measure the static voltage stability of power system, short circuit ratio is widely used in studying HVDC transmission system and multiple renewable energy stations. Based on the definition of multiple renewable energy stations short circuit ratio（MRSCR）, the effect of motor-generator pair（MGP） on MRSCR is studied. Firstly, we introduced the basic structure and characteristics of MGP and analyzed the promotion effect of MGP on the short-circuit capacity of the system. Based on Thevenin equivalent method and branch addition method, the influence of MGP on system structure and node impedance matrix were analyzed respectively. The influence mechanism of MGP on short circuit ratio is revealed. The theoretical derivation result shows that MGP can improve the short circuit ratio of the system. Finally, simulation model of three renewable energy stations was built in PSCAD simulation software. Combined with the theoretical calculation result of an example and simulation result, the effect of MGP system on MRSCR is verified. Furthermore, it is verified by simulation that MGP can restrain transient low voltage and transient overvoltage.