The invention discloses a method for connecting fiber reinforce plastic (FRP) ribs. A fusiform outer sleeve is used for connecting the two FRP ribs through dual effects including thread mechanical occlusion and gluing, and joint stress in the concrete is carried out. The method has the main characteristics that firstly an FRP material and thermoplastic epoxy resin are mixed to prepare the composite cylindrical connecting sleeve, after the sleeve is filled with thermosetting resin, the two FRP ribs are successively inserted into the sleeve for docking, and finally, a mold in a special shape isused for heating and pressurizing a sleeve and FRP rib whole, the thermoplastic resin of the sleeve material is softened, the sleeve material is pressed into a fusiform shape in the mold, the shape better reduces stress concentration, and the performance of the cured sleeve-FRP rib whole is excellent. The method is used for connection of the FRP ribs in concrete structures (beams, columns and thelike), has the characteristics of being convenient to construct, small in docking length and high in strength, and can ensure effective docking between the FRP ribs in concrete.