The present invention discloses an electronic watch automatic assembling mechanism. The electronic watch automatic assembling mechanism comprises a first assembling transmission band, a second assembling transmission band and a third assembling transmission band which are respectively arranged at the left portion, the middle portion and the right portion of the electronic watch automatic assembling mechanism, the first assembling transmission transmits a movement, the second assembling transmission band transmits a watch housing, and the third assembling transmission band transmits a cover. The second assembling transmission band comprises a left support side plate, a right support side plate, a reinforcement seat and a guide sleeve, there are four telescoping cylinders at the bottom portion of the second assembling transmission band, first connection bars are respectively installed at left and right sides of the extension bar of the second assembling transmission band, the first connection bars are connected with a clamp block. The mechanism also comprises a left support frame and a right support frame, a gear post, a second guide post, a left movement case and a right movement case, wherein a first guide post is arranged between the left support frame and the second support frame. The electronic watch automatic assembling mechanism can assemble four electronic watches at one time, after the shaped dimension of the electronic watch is replaced, a location die is not needed to be made once again, and the electronic watch automatic assembling mechanism has self learning function to optimize the assembling process, realize unmanned assembling of the electronic watch and reduce the production cost.