A free weight training protection device includes a rack, two transmission modules, a control module and a barbell. The rack includes hanger structures which are configured to be laterally symmetrical to each other. The two transmission modules are configured to be laterally symmetrical to each other. Each transmission module includes a motor, sprockets, chains, pulleys and ropes. When a controller executes a fitness program, the controller operates the motor, so that the rope maintains a basic tension which is a very small tension and will not affect the hand feel of heavy training. If the barbell has an abnormal position or displacement, the controller will start a protection program to prevent the barbell from falling and move the barbell upward, so as to provide protections to users.