The invention discloses a method for shaping and pruning an open center-shaped peach tree with three main branches. The method comprises the steps as follows: in the year when the peach tree is planted, the trunk is fixed at the height of 50-60 cm, three main branches are selected, and in the first winter, the three main branches are truncated and are kept for a 40-50 cm in length; in the second winter, 5-6 well developed shoots with wide angle are reserved and selected from lateral branches of each main branch, the rest of shoots are cut off from the base part, and when the lateral branches grow being 25-30 cm long, 3 exuberant lateral branches with twigs being uniform in thickness are reserved and selected as bearing branches; and in the third spring, relatively exuberant twigs on the lateral branches are subjected to top removal, the twigs are drawn in summer, the leading shoots are subjected to top removal in autumn, back branches, competitive branches and newly sprouting lateral branches are cut off from the main branches in winter, and in the fourth year, the branch drawing angle is further enlarged. According to the invention, on the basis that the three main branches form an open center shape, by the manage mode of supplementing summer pruning with winter pruning, the three outline of the peach tree is more reasonable, and bearing quality and quantity are increased.