The invention discloses a functional training aid for patients lying in a bed. The training aid comprises a base, a pull force assembly and a pedal assembly. The pull force assembly is fixed to the front end of the base, and the pedal assembly is rotationally fixed to the upper portion of the base. The training aid further comprises a fixing connection device used for fixing the base to the bed. The fixing connection device comprises a lateral fixing connection device body composed of lateral connection locking rods, the lateral connection locking rods are symmetrically arranged and located on the left side and the right side of the base respectively, each lateral connection locking rod comprises a transverse connection rod and a first locking mechanism, the inner ends of the transverse connection rods are fixed to the base, and the first locking mechanisms are locked to a lateral frame of the bed; the fixing connection device also comprises a rear end fixing connection device body fixedly locked to a bed tail frame or a bed tail plate. The training aid can be installed on the bed and has the function of helping the patients exercise upper limbs and lower limbs on the bed, the patients do not need to be looked after by medical staff, burdens of the medical staff are reduced, the training aid is simple in structure, easy to use and convenient to detach, fold and store, and the occupied space is reduced.