An air pump assembly is disposed within an inflatable article, and includes a movable member. When the movable member is moved relative to a base to an inflating position, an outflow outlet in the base is closed, and an inflow valve is activated to open an inflow outlet in the base so as to permit air to be sucked into the inflatable article through an inflow inlet and the inflow outlet in the base by an air pump. When the movable member is moved to a deflating position, the inflow inlet is closed, and an outflow valve is activated to open an outflow inlet in the base so as to permit air to be forced out of the inflatable article through the outflow inlet and the outflow outlet.