The invention provides an experimental device of FRP rib durability under stretching stress and environment coupling effect. The experimental device comprises a pull-down plate (1), a positioning plate (7), a pull-up plate (2) positioned between the pull-down plate (1) and the positioning plate (7), four pull rods (3) penetrating through the pull-up plate (20) and arranged between the pull-down plate (1) and the positioning plate (7) through a positioning nut (4), a pair of universal spherical hinges (8) with threaded rods, a sample loading sleeve (10), a glass tube (13) and a temperature controller (15), wherein a thrust augmentation nut (5) is arranged at the bottom of the pull-up plate (2); a spring (6) is arranged between the pull-up plate (2) and the positioning plate (7); holes are respectively formed in the middle parts of the pull-down plate (1) and the pull-up plate (2); the pair of universal spherical hinges (8) with the threaded rods respectively penetrate through the holes in the middle parts of the pull-down plate (1) and the pull-up plate (2) and are connected with the sample loading sleeve (10); a stress sensor (9) is arranged between the universal spherical hinges (8) and the pull-down plate (1); the stress sensor (9) is connected with a data collector (16); the glass tube (13) is connected with the temperature controller (15). The experimental device is high in precision, adjustable in stress level, uniform in stress distribution during the process of applying load for a long time, good in continuity, convenient in temperature control and high in reliability.