We carried out research on the development of a labor-saving system for grafting cucurbitaceous vegetables. Prior to the design of the system, we examined basic techniques such as grafting methods suitable for mechanization, seedling shape, location of cutting, seedling gripping, cutting, fixing tools, etc. Considering the rate of successful agglutination, the number of working processes, difficulties for mechanization etc., we examined various grafting methods and finally found that the “Cutting-off Cotyledon Grafting Method (CCG)” was the most suitable. The joint of cotyledons to the hypocotyl could be used as the standard for the location of cutting. High successful agglutination rate is obtained by reducing the grip compression strain of the hypocotyl below 30% of its diameter, cutting the seedling at the angle of 10 degrees for scions and 30 degrees for root stock, and using a manual grafting clip for fixing.