Abstract: To detect clock jump and gross error in data of satellite clock, a two-step method for error detection of satellite clock data is proposed by combining the single difference algorithm of epochs and quasi-accurate cetection method (QUAD). In the first step, a single difference algorithm of epochs is used to detect suspected clock jump and eliminate the gross error points according to the different performance characteristic of clock jump and gross error in the sequence of single difference of epochs; and in the second step, QUAD is used to detect gross error precisely for the data by segment according to the suspected clock jump. The detecting process is set forth and the performance is analyzed by using simulating data, and the algorithm is verified by practical data, both examples show that using only single difference algorithm of epochs can effectively detect suspected clock jump points and partial error, while using the two-step method can effectively avoid clock jump influence, and can accurately detect small gross errors, which is close to two times the background noise's standard deviation.