Abstract: Because of the multiple interfaces and the complex power supply condition, the strict time sequence control is needed when the satellite is being tested. In this paper, the impact of power-up time on the satellite is analyzed combined with typical trouble cases, then two common types of abnormal phenomena caused by it are found:1) the undetermined states caused by the insufficient power supply, 2) the abnormal data caused by the power-up time sequence. Finally, a practical check method is suggested for engineering designers.