The invention provides a satellite telemetry data outlier elimination pre-processing method, comprising: firstly, analyzing the structures of the telemetry frame of the satellite, determining the frame length, identifying fields such as frame synchronization heads, frame counts, check bits and check modes in the telemetry frame; secondly, creating a reading pointer, successively searching the frame synchronization heads backwards, reading frame data to cache according to the frame length, taking out the frame count and the check bits, finally, calculating check bits according to the check modes of the satellite telemetry frame, comparing, judging whether the frame count is legal according to a satellite telemetry download rule, comparing with a former frame, if the frame counts of the former and the next frames are continuous and the check bits are right, illustrating that the frame data are right data; if the frame counts of the frame data and the former frame data are discontinuous and the check bits are wrong, illustrating that the frame data are outliers and are eliminated. According to the invention, double conditions of the check bits and frame counts are compared, the outliers are judged accurately, the method is easily realized through programming, and the elimination efficiency is high.