Taking the Staubli TX90 six-axis industrial robot as an example, the communication process of process date object（PDO）in CANopen communication protocol was introduced. Under the condition that the robot controller did not support the electronic date sheet import, in order to solve the problem that the robot master station object dictionary did not set the object 0x6060 length according to the DSP402 device sub-profile, a method of adding objects to the external axis driver object dictionary was proposed. The 16-bit data sent by the robot controller was split, the low eight-bit data was stored in the external axis driver object 0x6060, and the high eight-bit data was stored in 0x607E. On the premise of not losing the transmission data of the robot, the network of the external axis driver and the robot controller was completed, and the synchronous movement of the external axis and the six axes of the robot body was realized.