The invention discloses a cam-crank-rocker combined flower transplanting mechanism and a design method thereof. A planetary gear transplanting mechanism is limited in flexibility of realizing a trajectory; and a rod mechanism with a double-ring-buckle trajectory is difficult in design and parameter regulation. According to the mechanism provided by the invention, one ends of a cam and a crank are both hinged with a frame through a camshaft; the other end of the crank is hinged with the central part of a second connecting rod; a forked swing rod comprises a bottom-end-welded oscillating rod and a cam swing rod; two ends of a spring are separately connected with the forked swing rod and the frame; a roller is hinged with the top end of the cam swing rod and constitutes a cam pair with the cam; the top end of the oscillating rod is hinged with one end of a first connecting rod; and the other end of the first connecting rod is hinged with one end of the second connecting rod. The design method provided by the invention is as follows: the cam is reversely solved with a mathematical model of a single-ring-button trajectory formed by the terminal point of the free end of the second connecting rod, a coordinate of the hinge joint of the forked swing rod and the frame, and known conditions of rod lengths. According to the invention, through changing of the profile of the cam to control the movement law of a rocker, the single-ring-buckle trajectory is realized, and the mechanism is simple.