Abstract: An automated method for measuring load-coaxiality of universal testing machine was presented in two aspects: basic hypothesis, math modeling for calculating and processing. Based on the principle the modeling concept was proposed. From the models posed, a measuring system using computer-testing technology had been designed,which used three raster strain sensors as well as digital converters and it can measure the load-coaxiality and direction directly in real time. The method holds strong adaptation and applied foreground in engineering.