A method for calculating performance of satellite gravity field measurement by low-to-low satellite-to-satellite tracking, includes: acquiring parameters of gravity satellite system; calculating an effect of satellite loads on the power spectrum of nonspherical perturbation potential, so as to obtain an degree error variance; comparing degree error variance with degree variance given by Kaula Rule, and when degree error variance equals degree variance, considering that the highest degree of gravity field measurement is obtained, calculating geoid degree error and its accumulative error, gravity anomaly degree error and its accumulative error, so as to obtain the performance of satellite gravity field measurement by low-to-low satellite-to-satellite tracking. The method is capable of evaluating gravity field measurement performance quickly and effectively, obtaining a rule of effects of the gravity satellite system parameters on the gravity field measurement performance, so as to avoid shortcoming caused by numerical simulation.