A spray washing component for a smart toilet cover and an assembly method thereof are provided. The spray washing component includes a base, a nozzle, and a first motor. A sliding track is disposed on the base. The nozzle has a rack cooperating with the first motor. The first motor drives the nozzle to slide along the base. The first motor is installed at an end away from a jet of the nozzle and drives the nozzle to be displaced through a transmission structure. The transmission structure includes a driving gear, a dual transmission gear, and a conveyor belt. The driving gear is in anti-rotation cooperation with an output shaft of the first motor. The dual transmission gear respectively meshes with the conveyor belt and the rack on the nozzle. The spray washing component and the assembly method solve the large space occupation and insufficient aesthetics of the existing toilet.