The Recess ratio (RR) is an important design parameter of gas-liquid coaxial swirling injector in liquid rocket engine. In this paper，an experimental investigation of the influence of RR on atomization properties of injectors has been carried out. The results show that there are certain differences between atomization properties of different injectors of different recess ratios under various working conditions. On the whole，the recess ratio does not affect the atomization so obviously as it does on the flux and mixing ratio characteristics. At low gas injecting drop，neither large RR nor small RR is favorable to atomization，on the contrary，both large RR and small RR will meliorate the atomization at high gas injecting drop. However，with too large RR，the liquid injecting drop vibrates owing to the interaction of between and liquid phases.