On the basis of the function relationship between phase shift and Doppler shift, the Doppler shift expressions only based on time difference measuring can be derived by the measurement equality for path length difference obtained from phase difference location equation and time difference location equation. The passive ranging formula based on Doppler shift measurement derived from Doppler equation can be transformed into one only based on time difference measurement. The error analysis shows that the passive ranging formula based on time difference measurement on motion platform has better measurement accuracy as compared to the ranging method based on Doppler shift measurement. As long as the moving distance of platform is larger than some kilometers, the technical requirement that relative ranging error is less than 5%R can be realized.