This paper presents an experimental study on the mixing characteristics of gas-liquid coaxial swirling injector of liquid rocket engine. A two-phase probe technique was employed to measure the distributions of gas and liquid mass flux and mixing ratio in sprays. The effects of the recess ratio of injector and the pressure drop of gas and liquid injection on the mixing characteristics were investigated. The results show that the recess ratio of injector plays a significant role in the mixing between gas and liquid flows from the coaxial swirling injector . Increasing the recess ratio will result in more uniform mixing between gas and liquid, and changing the pressure drop of injection will result in different distribution of mass flux and mixing ratio.