Abstract: When the moon and the sun light enters into the field of view of the conical scanning earth sensor (CES)，the real attitude of the spacecraft will be affected because of wrong CES measurements．To solve this problem，a new method based on the CES software can discriminate the interference effect．A series of ground are designed to verify this method effectiveness，and results indicate that this method can not only give a indication of the moon，but also can eliminate effect of the moon and the sun light on the CES’s measurements．Finally，the on-orbit flight data is presented to confirm this method validity．

Key words: conical scanning earth sensor software, discrimination, moon interference