An angle adjustment mechanism for LED bar lighting includes a lamp body, two end covers arranged two ends of the lamp body along an axial direction thereof, two lamp frames respectively mounted on the two threading pipes, two wheel gears respectively fixed on the two lamp frames, two outer end caps fixed and covered on the two end covers, respectively, and at least two stopping plates respectively received in the two lamp frames. Each of the two end covers includes a threading pipe extending along the axial direction of the lamp body. Each of the two wheel gears includes a plurality of gear teeth taken along a radial direction thereof and rotating around the threading pipe. Each of the stopping plates provides at least one stopping tooth which is coupling to the gear teeth.