The invention discloses a speed reduction clutch for a washing machine. The speed reduction clutch comprises a shell body, a brake wheel and an inner cylinder shaft connected with the brake wheel or an inner wheel train of the brake wheel, a first bearing is installed between the brake wheel and the shell body, and a second bearing is installed between the inner cylinder shaft and the shell body.The invention further provides an assembly method of the speed reduction clutch. According to the assembly method, the first bearing for supporting the brake wheel and preventing shaking of the brakewheel is arranged, the second bearing for supporting the inner cylinder shaft and preventing shaking of the inner cylinder shaft is arranged, and through the design of the first bearing and the secondbearing, better supporting and shaking prevention effects are achieved on the inner structure of the speed reduction clutch.