This present invention provides an automatic pot seedlings feeding mechanism for semi-automatic transplanter, comprising a transmission mechanism, a slider-crank mechanism, a stop lever, a side plate, a resetting mechanism and a bearing with bearing support. The transmission mechanism includes a transmission shaft I, a driving wheel, a transmission shaft II, a transmission shaft III and a conveyor belt. Under the performance of the conveyor belt, the pot seedlings are transported forward to the position of the stop lever. The slider-crank mechanism comprises a crank, a slider bar and a sliding chute, the crank and the driving wheel are connected through a revolute pair A, which is on the driving wheel, but not at the center of the driving wheel. The slider is securely connected with the resetting mechanism.
