Abstract:With the rapid development of laser cooling technology, cold atoms have become one of the key platforms for emerging quantum technologies, including quantum sensing, quantum precision measurement, quantum simulation and quantum computing. The temperature of cold atoms is an important parameter of the cold atom experiments. Ultra-cold atoms have a low collision rate, long coherence time, and reduced Doppler broadening. Therefore, temperature measurements on cold atoms are of great scientific significance and application value. In this article, the research progress of cold atomic temperature measurement methods is reviewed. Firstly, the design and implementation of a simple method to quickly and nondestructive measure the temperature of selected regions in the cold atomic ensemble. Secondly, the colder atoms with temperature less than 1 μK are filtered out from about an ensemble with 20 μK, and the original form of Maxwell′s demon model is demonstrated in the experiment.