In view of the current problems that the video extensometer is difficult to mark in practical applications and the mark is easy to fall off in the test, a set of video extensometer system that can realize high-precision displacement tracking measurement based on the texture characteristics of the rebar itself without special manual marks was designed for the performance test of rebar. The hardware composition, selection and basic working principle of the video extensometer measurement system were introduced. The image matching algorithm used was mainly studied, and the selection of the position and size of the matching template, the sub-pixel positioning algorithm based on surface fitting, and the update of the matching template in dynamic test were analyzed and discussed. Finally, static test, rigid displacement test and dynamic test all verify that the designed video extensometer system can meet the real-time and accuracy requirements of the measurements.