The moon cup comprises a holding part, a lantern ring, a discharge part, a valve part and a plurality of grooves.The accommodation part is provided with an opening at the top and a flow outlet at the bottom, and the cavity of the accommodation part is gradually reduced from the top to the bottom.The ferrule is arranged at the top of the accommodation part and surrounds the opening.The discharge part is hollow tubular, connected to the outlet of the accommodation part and connected to the cavity, and the external wall surface of the discharge part is provided with external threads.The valve part is provided at the bottom end of the accommodation part for closing or opening the flow outlet.A plurality of grooves are arranged on the wall surface of the accommodation part, under the collar, and extend longitudinally toward the discharge part.The invention also proposes a moon cup auxiliary device and a combination of the moon cup.一種月亮杯,包含容納部、套環、洩流部、閥門部及多個溝槽。容納部在頂端開設有開口,在底端開設有流出口,容納部的腔體自頂端至底端逐漸縮小。套環設置於容納部的頂端,環繞開口。洩流部為中空管狀,連接於容納部的流出口,連通於腔體,洩流部的外壁面上具有外螺紋。閥門部設置於容納部的底端,以用於封閉或開啟流出口。多個溝槽間隔的開設於容納部的壁面上,位於套環下方,在縱向上朝向洩流部延伸。本創作還提出一種月亮杯輔助裝置及月亮杯的組合。