Minimal change is a fundamental principle for modeling system dynamics. In this paper, we study the issue of minimal change for Computational Tree Logic (CTL) model update. We first propose five primitive operations which capture the basic update of the CTL model, and then define the minimal change criteria for CTL model update based on these primitive operations. We provide essential semantic and computational characterizations for our CTL model update approach. We develop a formal algorithm to implement this update that employs the underlying minimal change principle. We also present a CTL model update example using the well known microwave oven scenario.