The invention discloses a multi-joint mechanical arm coordinate correction method and a multi-joint mechanical arm coordinate correction system. The multi-joint mechanical arm coordinate correction method comprises the following steps: receiving initial parameters of a multi-joint mechanical arm, wherein the initial parameters comprise length and mass of each arm support; based on the initial parameters, calculating a first deformation amount produced by an arm support next to each arm support relative to each arm support, a second deformation amount produced by the load of the arm support and a third deformation amount produced by an arm support prior to each arm support relative to each arm support, calculating the total deformation amount of each arm support and determining the end deformation amount of the multi-joint mechanical arm; based on the current angle of each joint arm root and the end deformation amount of the multi-joint mechanical arm, determining the end point coordinate of the multi-joint mechanical arm. The multi-joint mechanical arm coordinate correction method and the multi-joint mechanical arm coordinate correction system have the advantage that the accurate control of the multi-joint super-long arm support is facilitated through the accurate positioning of the coordinate of the end of the arm support.