The invention provides a connecting device for fiber composite material ribs. The connecting device comprises a cylindrical sleeve, an adhesive capsule, a curing agent capsule and two anchoring devices, wherein a cavity is formed inside the cylindrical sleeve; through holes are formed in two ends of the cylindrical sleeve; the adhesive capsule and the curing agent capsule inside the cavity are respectively filled with an adhesive and a curing agent; connecting ends of two fiber composite material ribs extend into the cavity; the two anchoring devices are respectively fixed at connecting ends of the two fiber composite material ribs, and are used for breaking the adhesive capsule and the curing agent capsule after the connecting ends of the two fiber composite material ribs extend into the cavity. By adopting the connecting device, the problem that fixed connection of fiber composite material ribs is failed as iron wires are rusted can be avoided while longitudinal connection of the two fiber composite material ribs is completed, and meanwhile the problem that the surface structures of the fiber composite material ribs are damaged as centralized shearing force can be resulted from a bundling mode to the fiber composite material ribs can be also avoided, so that the properties of the fiber composite material ribs are improved, and the service lives of the fiber composite material ribs are prolonged.