The operation ability of the modified 2Arms drill rig of type CMJ227 was analyzed. The kinematics analysis was carried out on the 2Arms drill rig, based on the DH method to establish the kinematics equation, and the expression positive kinematic solution was deduced. By using the Monte carlo method to analyse the drill arm space, the working space of single arm operation and 2Arms collaborative working was gotten, and concluded of the best distance that drilling in the cross section of the dirll car at actual working was 1 010 mm. Through the drill car placed in an ideal position limited drill arm to be vertical to operation plane, the operating point of actual work of drill car was obtained. Analysis results show that the 2Arms work together has a larger work space, and the actual working range is all in accessible point in operation space.