The invention discloses a sine wave coupling. A driven sine wave fluted disc is connected with an output shaft, a driving sine wave fluted disc is connected with a driving shaft by virtue of a spline, and a down stroke is limited by virtue of a locating sleeve, a fixing pin and a split pin; the spline and the driving shaft, which are positioned above the locating sleeve, the fixing pin and the split pin, are sequentially provided with a spring, an adjusting nut and a locking nut; the adjusting nut is capable of adjusting a compression elastic force applied to the driving sine wave fluted disc by the spring; and the locking nut is capable of locking the adjusting nut so as to prevent loosening. The sine wave coupling is simple in structure, high in practicability and wide in application prospect; the sine wave fluted discs are capable of realizing repeated execution of transmission, slipping and differentiating; the output mechanical energy has the characteristics of differential motion, pulsation and vibration; furthermore, due to the sine wave characteristics of fluted surfaces, the smooth transitivity is especially excellent when the two fluted discs are subjected to repeated occlusion and slipping differential motion; when correctly used in special occasions, the sine wave coupling is capable of achieving unexpected new functions and characteristics; and by virtue of adjusting the compression force of the spring, the largest slipping output torque can be conveniently adjusted.