The utility model relates to a template system that is under construction in being used for narrow space, include: immediately, locate the first template of being close to narrow space, the nut has set firmly on the back of the body of first template is stupefied, immediately, locate the second template of keeping away from narrow space, the 2nd penetrating hole has been offered in the second template, prop up and locate first template with protective case between the second template, protective case's first end is worn out first template is stretched to the nut, protective case's second end is arranged in in the 2nd penetrating hole, the cover is located the sealing washer of the first end of protective case, and follow the 2nd penetrating hole stretches into split bolt in the protective case, the split bolt spiral shell fits nut and fastening first template with the second template. The sealing washer is set up, to sealing, the infiltration of concrete can be effectively prevented, because of the inspersed difficult problem of concrete when having avoided demolising split bolt between nut and protective case.