Abstract: A valve manifold box comprises a chamber and a front cover. Significantly, the chamber is manufactured by injection molding and is one-piece construction. Moreover, the chamber comprises a back board, a sidewall, at least an outfall, and multiple fittings and inside surface at the bottom sidewall has changes in an inclination angle for collecting the liquid within the chamber. By means of injection molding, one piece construction of the chamber is obtained such that it prevents chemicals from leaking outside. Besides, by using the design that the inside surface at the bottom sidewall has changes in an inclination angle, liquid can be easily collected and drained. Also, since it is unnecessary to frequently maintain the valve manifold box, maintenance costs are saved.