Seedling grading pick-and-place device and seedling pick-and-place method

The invention provides a seedling grading pick-and-place device and a seedling pick-and-place method. The device comprises an end effector, a seedling pick-up control mechanism, a transverse moving mechanism, a seedling withdrawing mechanism and a seedling recognition mechanism in communication connection with the seedling pick-up control mechanism and the transverse moving mechanism, wherein the end effector comprises an elastic pointer and a seedling protection plate component in sliding connection with the elastic pointer; the seedling pick-up control mechanism drives the end effector to move up and down, and the transverse moving mechanism reciprocates between a seedling hole tray and the corresponding hole tray; and the seedling withdrawing mechanism comprises a seedling withdrawing stop lever and a seedling withdrawing cylinder, the seedling withdrawing cylinder drives the seedling withdrawing stop lever to move to the position over the seedling protection plate component, and the seedling taking contro