A cover structure of a washer pump includes a base, a cover and a fastener unit assembled relative to each other. The base and the cover are fastened through the fastener unit, which facilitates the assembly and disassembly of the user. The locking member ensures that the fastener unit is in a locked state to provide a safety protection effect, which not only prevents the fastener unit from being opened by mistake, but also prevents the flow path from being too strong and causes the cover to escape the doubt of the base, thereby enhancing the The tightness of the combination of base and the cover is increased, which increases the fluency of water flow in and out, and at the same time enhances spa and massage effects.