An intake/outlet pipe optimization method for a rotary engine, comprising the steps of: (A) providing a rotary engine; (B) providing a simulation software package, to perform a series of simulations for the rotary engine according to different combinations of a pipe length, a pipe diameter, a pipe shape and a pipe angle, to determine an optimal combination of the pipe length, the pipe diameter, the pipe shape, and pipe angle, to obtain an optimal power output for the rotary engine; and (C) performing tests for the rotary engine, by utilizing the optimal combination of the pipe length, the pipe diameter, the pipe shape, and pipe angle obtained in step (B), to obtain a test optimized power output for the rotary engine.