The disclosure provides a control valve which includes a valve body having an inner space and a valve gate. The valve gate is movably located inside the inner space of the valve body and the valve gate has at least one main channel having two valve ports opposite to each other, and each of the valve ports of the main channel has a plurality of circular holes and a curved hole, where the circular holes are arranged in a line and the curved hole is connected to one of the circular holes that is located at an end of the line. The control valve has a lower flow rate limit which is greater than zero.