To realize exhaust gas recirculation (EGR) stratification in the cylinder of a motorcycle gasoline engine, so as to reduce pump air loss and NO_x emission, the intake bypass system in the original engine was transformed into an EGR system. The boundary conditions and initial conditions of the exhaust incident pipe, inlet and exhaust ducts under 3 000 r/min and 60 mg intake air were solved by using the GT-POWER model. These conditions were imported into the CONVERGE model of the engine for calculation, and the exhaust gas incident pipe parameters were determined by comparing the flow characteristics, velocity field and exhaust gas mass fraction in the cylinder under different exhaust gas incident pipe diameters, installation angles and installation distances. The results show that under the condition of 3 000 r/min and 60 mg intake air, EGR stratification can be realized in the cylinder when the exhaust gas incident pipe diameter is 5 mm, the incident pipe inclination angle is 17.5° and the installation distance is 22 mm.