The utility model relates to a water tap with easy assembly and precise leakage prevention, which mainly comprises a box body of a water control valve base, an O-shaped leak-proof ring, an annular gasket, a water tap casing and a positioning sleeve. The utility model is characterized in that the O-shaped leak-proof ring is arranged at the middle section of the box body of a water control valve, a rubber gasket coated with a metal ring is sheathed at the bottom end of the box body and the box body of the water control valve is also matched with the water tap casing which is provided with an accommodating chamber of the water control valve with the inverted conical space. The positioning sleeve is used to combine in a screw fixing mode the box body of the water control valve and the water tap casing, the O-shaped leak-proof ring is forced to tightly abut against the circumferential wall of the accommodating chamber, the annular gasket is tightly propped against the bottom wall of the accommodating chamber, so the efficacy of quick assembly, precise positioning and leakage prevention is achieved.