The invention relates to a method for determining the safety use boundary of a quartz flexible accelerometer. The method comprises the following steps of: 1, performing a high-temperature stepping stress test of the quartz flexible accelerometer; 2, performing a low-temperature stepping stress test of the quartz flexible accelerometer; 3, performing a quick temperature change stepping stress testof the quartz flexible accelerometer; 4, performing a vibration stepping stress test of the quartz flexible accelerometer; and 5, determining the safety use boundary of the quartz flexible accelerometer, namely taking each stress working limit determined by the variation of performance parameters and a strengthening test as the safety use boundary of the quartz flexible accelerometer. In the method, the functional characteristic and the characteristic of the variation of the performance parameters are taken into consideration by a method of the strengthening test to provide the safety use boundary of the quartz flexible accelerometer, so the test time is shortened and a basis is provided for the selection of the stress condition of an accelerated life test or an accelerated degradation test of the quartz flexible accelerometer.