Abstract:Phase difference is an extremely important parameter in many fields such as electrical technology, industrial automation, intelligent control, communications and electronic technology etc. This article describes the basic principles of three types of phase measurement algorithm, which is over-zero method, correlation method and spectrum analysis method, and achieves them with LabVIEW respectively. At the same, the causes of errors of these three algorithms are analyzed and the method of improving the measurement accuracy is proposed. Finally, through a comparative analysis of the three algorithms, the applicable occasions for each algorithm are offered.