Testing is the premise and foundation of realizing equipment health management (EHM).To address the problem that the static periodic test strategy may cause deficient test or excessive test,a dynamic sequential test strategy (DSTS) for EHM is presented. Considering the situation that equipment health state is not completely observable in reality,a DSTS optimization method based on partially observable semi-Markov decision process (POSMDP) is proposed.Firstly,an equipment health state degradation model is constructed by Markov process,and the control limit maintenance policy is also introduced. Secondly,POSMDP is formulated in great detail.And then,POSMDP is converted to completely observable belief semi-Markov decision process (BSMDP) through belief state.The optimal equation and the corresponding optimal DSTS,which minimize the long-run expected average cost per unit time,are obtained with BSMDP.The results of application in complex equipment show that the proposed DSTS is feasible and effective.