The invention discloses a device and method for improving uniformity of each cylinder in gasoline engine exhaust gas recirculation. The device comprises an intake manifold and a gasoline engine throttle valve body connected with the intake manifold, and further comprises a gas mixing device, wherein one end of the gas mixing device is connected with the intake manifold, and the other end of the gas mixing device is connected with the gasoline engine throttle valve body. The method for improving the uniformity of each cylinder in the gasoline engine exhaust gas recirculation is achieved through the device for improving the uniformity of each cylinder in the gasoline engine exhaust gas recirculation. According to the device and the method, the independent gas mixing device is adopted, the gas mixing device is respectively connected with the gasoline engine throttle valve body and the intake manifold, vortexes behind a throttle valve of the gasoline engine throttle valve body is sufficiently utilized to increase mixing capacity, exhaust waste recirculation gas mixing uniformity is greatly improved, power performance of an engine is improved, and the average EGR relative error of each cylinder is controlled to be within 3.5%; meanwhile light-weight production requirements for gasoline engines can be met.