Abstract: With the proposal of the Micro-PNT（Micro-Technology for Positioning, Navigation and Timing）by United States Department of Defense Advanced Projects Research Agency(DARPA) and the development of unmanned technology, the market of chip-scale atomic clock has attracted much attention.Stability is a key parameter of the performance of chip-scale atomic clock, which is affected by the accuracy of temperature control, so a high accuracy temperature-control system is very essential to the stability of chip-scale atomic clock.  A digital temperature-control system with high accuracy is designed，and its precision is 2mK. The test results show, the stability of chip-scale atomic clock is greatly improved from 7.57×10^-12to 4.99×10^-12, which is in a world level.

Key words: Chip scale, Atomic clock, Temperature, Accuracy, Digital temperature control, Stability