In networking test of optical equipment, radar and GPS on precision-guided weapons and unmanned aerial vehicle, time delay caused by equipment synchronism, communication transmission and data processing has a deep influence on guidance accuracy and reliability. In order to solve the problem, a new method to isochronously calibrate whole-networking time, acquire time delay accurately and fix it with the least-square method was introduced. Then a time delay correction model was proposed. It has been proved that the method can significantly improve equipment guidance accuracy, stability and reliability in the networking test, which provides strong technical support for remote distance and high-precision trajectory parameters measurement.