A numerical simulation was performed to investigate the film cooling performance of a multi-element splash platelet injector. A 16-species, 41-reaction mechanism and an eddy-dissipation concept model were used for the simulation of turbulent combustion. The effects of typical film cooling parameters, such as injection slot height, slot geometry, mixture ratio, and injection position, were studied. An increase in slot height caused a direct decrease in velocity ratio and film coolant length and an increase in wall temperature in the combustion chamber head. Slot height, slot geometry, and mixture ratio exerted minimal influence on wall temperature. However, changes in slot geometry and injection position remarkably influenced the injector faceplate temperature. The size of the high-temperature zone of the faceplate increased with the change in slot geometry. When the injection position changed, the location and scope of the high-temperature zone also changed. Furthermore, two recirculation zones were observed near the injector post. These recirculation zones considerably affected film cooling performance, and the upper recirculation zone exerted an adverse influence on cooling performance in terms of faceplate temperature. Therefore, an appropriate design of the cooling slot should be selected to improve film cooling performance.