An optoelectronic measurement method for real-time monitoring deformation of the large-scale platform is presented. This method place some linear array CCD as a high benchmark test at various location for measurement, and makes use of the laser as line source so that the linear array CCD of different positions receives the same signal of beam of light at the same time. Then, linear coordinate transformation is used to transfer location information of height which linear array CCD receives into elevation output whose baseline is coincident with other coordinate. Compared with each high value data in different load conditions or at different moments at last, real-time relative deformation of points is obtained in the platform. The method brings about good results in practical application.