A combined pilot valve mechanism and a shower system are applied with the combined pilot valve mechanism. By switching to close the control hole, the first water diversion hole or the second water diversion hole to control the pressures of the pressure cavity, the valve spool is driven to move to alternately close the first outlet or the second outlet, so that the inlet waterway is switched to connect to the first outlet waterway, the first water diversion hole or the second water diversion hole. As the shower system is applied with a combined pilot valve mechanism, which utilizes the control hole to switch the waterways, thus preventing the main pipe from great water pressure. The diameter of the control hole can be smaller, so that the water pressure of the button mechanism can be ignored, only friction and light elastic force of the spring exist.