Abstract: Space coordinate transformation is widely used in geodetic surveying and engineering surveying field. When using the common point to solve the coordinate transformation parameter, the coordinate system transformation model based on Rodriguez matrix was given and a coordinate transformation robust algorithm based on Random Sample consensus (RANSAC) was proposed for the problem of multiple rough points in the common point. At the same time, the algorithm was compared with the least squares robust algorithm based on IGG3 scheme. The results of the example show that when the rough points ratio exceeds 3／10 in the simulation of 20 common points(multiple sets of data), the least squares robust algorithm based on IGG3 scheme begins to fail, while the coordinates transformation robust algorithm based on RANSAC can also ensure the accuracy of coordinate transformation, even if the rough points ratio reached 1／2. The robust algorithm applies the idea of the RANSAC algorithm to the coordinate system transformation and effectively eliminates a large number of rough points that are mixed in common points.