Future space missions are considering the use of green space propulsion, and H2O2/kerosene bipropellant is one of effective alternatives for rocket propellant. In addition, for a 100-N-class thruster of H2O2/kerosene, it is important to design the proper injector. In this study, according to different values of the geometric constant A which determines the initial swirl intensity of the injected fluid, five coaxial swirl injectors are designed to check the thruster's performance. From the test and experiment results, it is found that with an increase in A, coaxial-swirl injectors can aid in the mixing of oxidant and fuel but increase the average temperature of faceplate, thus significantly reducing the flame length. However, a large or small value of A is not conductive to improve the combustion efficiency. In addition, the pressure oscillation (P-ins) inside of the chamber gradually becomes intense. Among all cases, Case 3 (A = 3.0), exhibits optimal performance for a 100-N-class H2O2/kerosene thruster. (C) 2017 Elsevier Masson SAS. All rights reserved.