Abstract: This paper presents the modified force limited specifications of the sine vibration test for the spacecraft system based on the quasi-static loads given by the launch vehicle providers, and makes comparisons in three typical simulation cases with the traditional specifications used by engineers working for spacecraft programs. It is shown that the modified force limited specifications and their corresponding acceleration notch levels have a clearer physical concept and more rational calculation methods. since the futile items in the resultant interface forces or moments of the quasi-static loads are eliminated. Besides, the modified specifications specify evidently less restricted conditions than the traditional ones and thus help to reduce the over-test problems in the vibration tests for the spacecraft system.