The basic fuel injection quantity was the basic data for develop the engine electronic fuel injection system. In the foundation of the common engine mean value model, the mathematical model of the rotary engine was established based on the structural characteristics of a certain type of rotary engine. The basic fuel injection quantity MAP of the rotary engine was simulated in Matlab/Simulink, and the accuracy of the simulation results were verified by the bench test. The final result shows that the error between the basic fuel injection quantity and the measured value is less than 10%, the basic fuel injection quantity MAP can be used as the initial injection MAP of the electronically controlled rotary engine and used in the design and research of the rotary engine electronic fuel injection system.