The invention discloses a control system of a painting robot. The control system is composed of a first controller in communication with an upper computer, a second controller in communication with the upper computer, a main control board in n communication with the upper computer, and a first controller. The first controller drives a paper moving mechanism by a first motor; and the paper moving mechanism is used for controlling a piece of painting paper to move on a painting board. The second controller drives an X-axis moving mechanism by a second motor; and the X-axis moving mechanism is used for controlling the painting module to move in a horizontal direction. The main control board is used for controlling a steering engine of the painting module; and the steering engine is used for driving a painting brush for painting. The first controller, the second controller, and the main control board are controlled in a unified manner based on instructions from the upper computer. The control system has advantages of low cost, simple structure, capability of being easy to maintain, low learning cost, low usage cost, capability of being convenient to construct, and high compatibility.