The utility model discloses an unilateral bolt tightening mechanism belongs to bolt technical field. The utility model discloses a " Z " style of calligraphy gasket, fixed plate, spring hinge, nut, nut, solid shim etc. The fixed plate is connected in the spot welding of the top of nut, evenly installs a plurality of elasticity hinges on the fixed plate, rotatable the fixing on the fixed plate of one end of every elasticity hinge, and the tie point of elasticity hinge and fixed plate does not surpass the outer edge of fixed plate, and the other end spot welding of every elasticity hinge is connected with " Z " style of calligraphy gasket, and a plurality of under the initial condition " Z " style of calligraphy gasket closes on the outer wall of nut along the equal cloth piece of circumferencial direction, when needing to pass in the mounting hole, a plurality of " Z " style of calligraphy gasket can turn over through the elasticity hinge to be rolled over to the nut top and forms the elastic potential energy of kick -backing, the utility model discloses a simple swift unilateral construction bolt can wide application in civil engineering and building construction, mechanical engineering etc..