Abstract: In this paper,summarize the application of platelet injectors in liquid propellant engines for spacecraft. Attention is focused on the performance and usefulness of platelet injectors used in space shuttle orbital maneuvering engines,small thrust attitude control engines and gas generators which are higher than those of conventional ones.Analyses are also made on the effect of platelet injectors used in small thrust liquid engines on decreasing exhaust plume contamination. Finally, the tasks are gi yen for further studying and desinging platelet injector.