The invention provides a simulation method and device of a digital twin system of an industrial robot. The simulation device comprises the industrial robot, a vision perception unit and a computer, wherein the vision perception unit is arranged at the tail end of the robot and is composed of a camera and a wire structure light emitter; an industrial robot simulation system is established, the robot is modeled, and three instructions are analyzed and run; a target three-dimensional measurement model of a robot visual system is acquired by using a wire structure optical geometric triangular method; a motion instruction is determined for the working task of the robot, virtual simulation is carried out through the computer, and reachable points and collision point detection are carried out; and the robot is actually used for identifying a target object through the visual perception unit, and the actual movement of the robot is driven. The simulation device is safe and reliable in virtual simulation, abnormal operation possibly in actual operation is avoided, the visual perception unit is used for identifying the target object through three-dimensional visual technology, the self-adaptive capacity of the robot to the field environment is improved, and flexibility and intelligence are enhanced.