The invention discloses a resistance point welding servo system. The resistance point welding servo system comprises a control chip, a servo driver, a DA chip, a servo motor electrically connected with the servo driver, a welding electrode connected with the servo motor and a grating ruler used for detecting the position of the welding electrode in real time, wherein the servo driver and the DA chip are electrically connected with the control chip. The grating ruler is electrically connected with the control chip. The DA chip is electrically connected with the servo driver and used for outputting the corresponding voltage to the servo driver according to a control command of the control chip. The servo driver works in a torque mode and is used for determining the motion direction of the servo motor and the output torque according to the voltage value and sending the voltage value to the control chip. The control chip carries out closed-loop control according to the received voltage value and the received position of the welding position. According to the resistance point welding servo system, composite control of welding penetration and welding pressure can be achieved, precision is high, and the dynamic response speed is high. The invention further discloses a precision resistance point welding machine with the resistance point welding servo system. The precision resistance point welding machine also has the above technical effects.