Abstract: A method to calculate lifetime of debris generated from spacecraft breakup events was presented. Based on NASA standard spacecraft breakup model, a spacecraft breakup algorithm was given, which yields a set of parameters of produced fragments that can serve as input for lifetime calculation. Current space debris lifetime algorithms were summarized and a semi-analytical algorithm was developed. By means of mean element method, rate of change of semimajor axis and eccentricity of fragment were calculated, in which J2 short-period variation was considered. Differentiation-integration method was applied to propagate the semimajor axis and eccentricity forward into time. Besides, calculation step of the algorithm was constrained to cooperate with time-varying atmosphere model. The computational speed and accuracy of the lifetime algorithm was analyzed through comparisons with a numerical orbital propagator. In order to find a suitable atmosphere model for lifetime calculation, three typical atmosphere models: SA76, GOST and MSIS-00 were compared. Finally, P-78 satellite breakup event was applied to test the whole algorithm.