A new method with multi-section swirl injection method is proposed in order to improve fuel regression rate of hybrid rocket engine. The new method is to introduce swirling flow through injector ports, which are placed at several cross-sections along the fuel grain. In the present study, combustion tests for several grain types have been conducted to clarify influences of difference in the number and direction of swirl on the regression rate. Visualization of combustion chamber of hybrid rocket engines has been conducted and swirling turbulent flow has been observed. Also, throttling of hybrid rocket engine has been conducted successfully. To realize Multi-Section Swirl Injection Method for real flight, two-module type flight engine with swirl injection has been proposed and applied to flight experiment. Hybrid rocket engine with multi-section swirl injection method has been successfully tested under 2G acceleration environment.