In this paper, we merge software trustworthiness with software design and present an approach to trustworthy software design with an automatically adapting software update. First, software behavior and results can be expected and behavior states can be monitored when a software runs by introducing a trustworthy behavior trace on a software and inserting a checkpoint sensor at each checkpoint of the trustworthy software. Second, an updated approach of the trustworthy behavior trace for the software at the level of checkpoints is presented. The trustworthy behavior traces of the software for two versions can be merged adequately by constructing split points and merge points between two trustworthy behavior traces. Finally, experiments and analyses show that： （1） the software designed by our approach can detect and report the anomaly in a software automatically and effectively, so it has a higher ability of trustworthiness evaluation than the traditional software; and （2） our approach can realize the accurate update of the trustworthy behavior trace with a lower space overhead of checkpoints when the software updates.
