A fluid purification device includes a screen plate, a first filtration layer, a second filtration layer, a third filtration layer, a main body, and a dispensing plate. The screen plate has a plurality of inflow holes for filtering particles in fluid passing therethrough. Around a periphery of the screen plate, several convex sections are arranged and spaced apart from one another. The main body is hollow and has an open top and an open bottom opposite to the open top. Around an inner wall of the open top, several concave sections are arranged and spaced apart from one another. The concave section is shaped in conformity with the convex section, so that the screen plate can be secured to the open top of the main body.