A robotic tool changer system, comprising: a first coupling unit (1, 1A, 1B, 1C), fixed to a robot arm end shaft, the first coupling unit (1, 1A, 1B, 1C) having a protruding portion (13, 13A), the protruding portion (13, 13A) having a first guide hole extending along a third direction, a first ejector pin being provided in the first guide hole, the first ejector pin providing a first acting force; a plurality of second coupling units each connected with a tool, each second coupling unit having a recess (33, 33A) corresponding to the protruding portion (13, 13A), each second coupling unit including a movable second ejector pin in the third direction and a movable guide lock, wherein the second ejector pin is configured to be driven by the guide lock to extend out of the recess (33, 33A) or retract into the recess; a plurality of tool changer grippers (2, 2B), each changer gripper including a third force-applying member (21, 21B) and at least one protruding post, each second coupling unit being detachably connected to a corresponding one of the tool changer grippers (2, 2B); wherein the robotic tool changer system is configured such that when the robot arm end shaft drives the first coupling unit (1, 1A, 1B, 1C) to move in a second direction to contact a selected one of the second coupling units, the protruding portion (13, 13A) is mated with the recess, an angle is defined between a first direction and the second direction, the robot arm end shaft pulls the first coupling unit (1, 1A, 1B, 1C) and the selected second coupling unit away from the corresponding tool changer gripper (2, 2B) along the first direction, the guide lock applies a second acting force to overcome the first acting force to drive the second ejector pin to push the first ejector pin so that the second ejector pin extends into the first guide hole, and the first coupling unit (1, 1A, 1B, 1C) is coupled with the selected second coupling unit; wherein the robotic tool changer system is configured such that when the robot arm end shaft drives the first coupling unit (1, 1A, 1B, 1C) and the selected second coupling unit to move to the corresponding tool changer gripper (2, 2B) along the first direction, the protruding post pushes the guide lock to overcome the second acting force, the first ejector pin pushes the second ejector pin through the first acting force so that the second ejector pin is retracted into the recess, the third force-applying member (21, 21B) applies a third acting force to hold the selected second coupling unit, and the first coupling unit (1, 1A, 1B, 1C) is moved away from the selected second coupling unit (3, 3A, 3B, 3C) along the second direction. a first coupling unit (1, 1A, 1B, 1C), fixed to a robot arm end shaft, the first coupling unit (1, 1A, 1B, 1C) having a protruding portion (13, 13A), the protruding portion (13, 13A) having a first guide hole extending along a third direction, a first ejector pin being provided in the first guide hole, the first ejector pin providing a first acting force; a plurality of second coupling units each connected with a tool, each second coupling unit having a recess (33, 33A) corresponding to the protruding portion (13, 13A), each second coupling unit including a movable second ejector pin in the third direction and a movable guide lock, wherein the second ejector pin is configured to be driven by the guide lock to extend out of the recess (33, 33A) or retract into the recess; a plurality of tool changer grippers (2, 2B), each changer gripper including a third force-applying member (21, 21B) and at least one protruding post, each second coupling unit being detachably connected to a corresponding one of the tool changer grippers (2, 2B); wherein the robotic tool changer system is configured such that when the robot arm end shaft drives the first coupling unit (1, 1A, 1B, 1C) to move in a second direction to contact a selected one of the second coupling units, the protruding portion (13, 13A) is mated with the recess, an angle is defined between a first direction and the second direction, the robot arm end shaft pulls the first coupling unit (1, 1A, 1B, 1C) and the selected second coupling unit away from the corresponding tool changer gripper (2, 2B) along the first direction, the guide lock applies a second acting force to overcome the first acting force to drive the second ejector pin to push the first ejector pin so that the second ejector pin extends into the first guide hole, and the first coupling unit (1, 1A, 1B, 1C) is coupled with the selected second coupling unit; wherein the robotic tool changer system is configured such that when the robot arm end shaft drives the first coupling unit (1, 1A, 1B, 1C) and the selected second coupling unit to move to the corresponding tool changer gripper (2, 2B) along the first direction, the protruding post pushes the guide lock to overcome the second acting force, the first ejector pin pushes the second ejector pin through the first acting force so that the second ejector pin is retracted into the recess, the third force-applying member (21, 21B) applies a third acting force to hold the selected second coupling unit, and the first coupling unit (1, 1A, 1B, 1C) is moved away from the selected second coupling unit (3, 3A, 3B, 3C) along the second direction.