A variable intake system for a vehicle is provided and includes an air cleaner that filters air via a filter and supplies the air to an engine. A main duct is connected to the air cleaner to supply the air, and a variable valve has a housing that is coupled and mounted to a mounting aperture of a mounting part disposed on a front end of the filter of the air cleaner. An internal passage of the housing is opened by suction pressure of the engine in the mounting part to suction external air. A projection formed on the housing of the variable valve is inserted into a projection seat formed in the mounting part, so that the variable valve is secured to the mounting part.