A flow limiting device with a back flow prevention mechanism includes a body that has an isolation board and a water-through cavity. The isolation board has a water-through hole connecting to the water-through cavity and a flow limiting device having a flow limiting component and stop ribs which limit the position change of the flow limiting component. The stop ribs are arranged on the inner wall of the water-through cavity at equal intervals. The flow limiting component is set in the water-through cavity. The outer side of the flow limiting component is contacted on the stop ribs. A back flow prevention mechanism comprises, a back flow prevention component which is fixed in the water-through hole and a supporting structure which is set for supporting the back flow prevention component when it expands on the inner wall of the water-through cavity.