The invention discloses a novel unilateral bolt fastener simple to use. The novel unilateral bolt fastener comprises a round head bolt and an anti-drop mechanism, wherein a rod body of the round head bolt is sleeved by the anti-drop mechanism; the anti-drop mechanism comprises a blocking mechanism and a fixing mechanism; and the blocking mechanism comprises a sleeve body, three supporting seats, three grooves, elastic ring bodies, fixed seats, three blocking bodies, three connecting bodies and several retaining bodies, wherein the sleeve body is in threaded connection with the round head bolt, the front end of the sleeve body is provided with the three supporting seats configured to form an isosceles triangle, each of the three supporting seats is provided with one of the grooves, each groove is internally provided with one of the elastic ring bodies, each elastic ring body is provided with one of the fixed seats between every two adjacent supporting seats, the front end of each fixed seat is provided with one of the connecting bodies, and each fixed seat is provided with one of the blocking bodies. Compared with the prior art, the novel unilateral bolt fastener can be used for realizing unilateral fastening operation, can also be conveniently dismounted as required and can be repeatedly used.