Taking Delta robot as the object of analysis, studying the position error model of the moving platform, and the coupling characteristic of the error source is analyzed. Using the position characteristic of driven arms, based on the method of geometry space vector, the mechanism error model of Delta robot is established; Using the principle of mathematical statistics and space vector as the basic, the joint clearance error model of Delta robot is derived; Based on finite element theory, on the basic of elastic dynamic model of Delta robot, the flexible error model is eatablished; Then, considering the three kinds of error source, the comprehensive position error model of Delta robot is established. Finally, by use of simulation software of Adams and Workbench, numerical calculation of Matlab and field experiment of FARO laser tracker, the correctness of comprehensive position error model is verified, and coupling characteristics of the error sources are analyzed, the relationship between position error and the axis's azimuth of system coordinate is elaborated. The results show that the error sources that affect the position error of the Delta robot's moving platform are not simply superimposed, but with obvious coupling properties, and the directional position error of the moving platform changes with the azimuth of the coordinate axis.