In order to calculate the statically determinate restraint load of the full scale or large scale parts of aircraft structure static test with the different statically determinate support quickly and accurately, a general solution method was first proposed, the calculative Matlab program also has been completed. The calculation of restraint load under constrained components as critical location with heavy load and large displacement, large deformation wing conditions was mainly investigated. A way of estimating the accuracy of loading system through the restraint load error was summarized based on several years of airplanes test experiences. The achievement above-mentioned was applied on a large passenger aircraft static load test successfully, providing an important basis to estimate the loading accuracy in real-time; the result of test indicates that the methods and program is accurate and reliable, which is popularized and applied to other aircraft tests.