A control system for a hydraulic variable valve. The control system may include an OCV configured with a housing, a flow passage defined in the housing, a main port, first and second drain ports, a spool, and a relief valve; a main line connecting the main port and the oil pump to each other; a control line connecting the control port and the lash adjuster to each other; an orifice provided between the main line and the control line; and a controller controlling the OCV to allow at least one combination of the main port and the first drain port, the control port and the second drain port, and the main port and the control port to communicate with each other.