The invention relates to a three-dimensional model conversion technology, and aims at solving the problems of heavy workload, many artificial influence factors, low working efficiency and low mapping accuracy as auxiliary lines are required to be made when a pelton model turbine synthetic characteristic curve is converted into a pelton prototype synthetic characteristic curve at present. According to a generation method of a pelton prototype turbine synthetic characteristic curve disclosed by the invention, coordinates of points on respective equal efficiency curves, equal power output curves and equal nozzle opening curves under respective nozzle numbers of a prototype turbine are calculated by means of computer software according to a model turbine synthetic characteristic curve; respective isolines under the respective nozzle numbers corresponding to a model turbine are drawn on an H-P planar coordinate graph and a Q-H planar coordinate graph respectively. The generation method is applicable to converting the pelton model turbine synthetic characteristic curve into the pelton prototype synthetic characteristic curve, wherein the model turbine synthetic characteristic curve consists of the equal efficiency curves and the equal nozzle opening curves in a plane graph where a turbine head coefficient is vertical coordinate and a flow coefficient is a transverse coordinate.