Abstract: To address the issue of power attenuation in aviation two-stroke piston engines with increasing altitude, a certain type of aviation two-stroke piston engine was taken as the research object, an exhaust resonant pipe was designed, an engine performance simulation model using GT-POWER software was established and validated, and the influence laws of structural parameters of each section of the exhaust resonant pipe on engine performance was analyzed by investigating the response mechanism of the exhaust resonant pipe. The research results show that the designed exhaust resonant pipe can increase the engine power by up to 59.46% and reduce the fuel consumption rate by up to 35.38%. An increase in pipe length shifts the exhaust resonance matching point to lower speeds, among which the divergent pipe length has the most significant impact with a maximum power decrease of 29.70%, while the tailpipe has the least impact with a maximum power decrease of 0.57%. Angular parameters are the main factors affecting the amplitude change of reflected waves. Increasing the divergent pipe cone angle from 6° to 10° can reduce the trough of the reflected pressure wave by 8.53%, and increasing the tapered pipe cone angle from 20° to 30° can increase the peak of the positive pressure wave by 4.92%. The reflected pressure wave further affects the exhaust mass flow rate and engine performance. When the trough of the reflected pressure wave decreases by 15.91%, the exhaust mass flow rate increases by 41.66% and the power improves by 62.92%. When the peak of the reflected pressure wave rises by 9.13%, the backflow of the exhaust mass flow rate increases by 393.13% and the fuel consumption decreases by 29.39%.