Abstract: Checkpointing is one of the important recovery techniques of real-time main memory database systems (RTMMDBS). Through analyzing the data characteristics in RTMMDBS, a method to calculate data checkpointing priorities is presented, which takes the timing constraints of both data and transactions into consideration. A partition fuzzy checkpionting strategy based on data segment checkpointing priority—PFCS-SCP is suggested, and the correctness of PFCE-SCP is also discussed. It is shown through performance testing that PFCS-SCP strategy can decrease the missing ratio of transactions in RTMMDBS.