This study was conducted to develop a root-removed splice grafting system for cucurbitaceous vegetables, mainly watermelon and cucumber seedlings, for the seedlings factories where currently most of seedlings grafting works are carried out by manual works. The major results of the study are as follows. The dimensions of rootstocks and scions, except cotyledon width, of root- removed splice grafting of watermelon and cucumber were shown to be varied within the 2.5-fold range. The growth status of seedlings were not consistent in terms of cotyledon sprouting direction and angle which were considered as one of the important factors for in root-removed splice grafting. The grafting work of root-removed splice for grafted watermelon and cucumber could be divided by four sub-operations: seedling supplying, cutting, clipping and potting, while a part or all root of the rootstock was removed in the seedlings supplying operation. The cutting angles of the rootstock and scion were $34-45^{circ}$ and $20-45^{circ}$, respectively, while the stem length of the scion varied from 6 mm to 12 mm. The splices of rootstock and scion were heaped up in parallel and then fixed by a clip. It indicated that the ideal grafting system, adopting conventional grafting processes of seedlings specifications as well as conventionally manual root-removed splice grafting method, performed very well for seedlings gripping and transporting, supplying clip, clipping and discharging grafted seedlings while workers supplied seedlings to the semi-automatical system.