4 species of temperate fern, Adiantum pedatum, Pteridium aquilinum, Dryopteris erythrosora and Lepisorus thunbergianus in sporophyte stage were subjected to soil water deficit to investigate photosynthetic response. They have different sporophyte morphology and habitats. Frond morphology of ferns is considered to be adapted to their habitats for effective photosynthesis. Stomatal density (SD), leaf mass per area (LMA) and Rubisco content were compared. Open site fern, P. aquilinum had highest SD and showed highest maximam photosynthetic rate. Rubisco content of P. aquilinum was as much as D. erythrosora. D. erythrosora had higher rubisco content than the other ferns but SD was lower than others. It showed lower photosynthetic rate and higher water use efficiency than others. Stomatal density is one of the main factors determining photosynthetic rate. In drought condition, both of stomatal conductance and photosynthesis decreased concurrently. In all of the ferns, Rubisco content did not change in drought stress, so low stomatal conductivity is a main reason to reduce photosynthetic rate. Epiphytic fern, L. thunbergianus did not have high water use efficiency but showed negative transpiration in drought stress. L. thunbergianus is considered to be poikilohydric fern and absorbs moisture when it is in sever drought stress.