Electronic equipments and make other electronic systems to operate abnormally by means of electromagnetic interference, or can operate abnormally themselves by electromagnetic interference of other electronic systems. Therefore, electronic equipments are required to reduce their electromagnetic interference as small as for other systems to operate properly and operate properly within electromagnetic interference from other electronic systems. In order to prove that electronic equipments meet such requirements, they should undergo electromagnetic environmental test. In this study, we introduce electromagnetic environmental requirements, test procedures and test results of gimbal engine actuation system of KSR-III.