Abstract: The final results of the Gravity Probe B (GP-B) experiment for testing general relativity (GR) theory published on May 4,2011 by NASA is somewhat controversial.Since GP-B scientific sensors have symmetric property about the satellite spin axis,the author believes the measurement errors of both the geodetic effect and the frame-dragging effect should be close to each other.However,in the published results,the former is 2.5 times of the latter,which has not been explained by GP-B final report and thus shows that some physics is probably still missing or inadequately addressed in processing experimental data.