At atmospheric pressure, vapor-liquid equilibrium relationships for five binary systems of methanol-tert-butylalcohol, methanol-tert-butylmethylether, tert-butylalcohol-tert-butylmethylether, water-tert-butylalcohol and water-tert-butylmethylether are observed. The Wilson parameters for the binary systems have been obtained. Comparisons between the Wilson method, The ASOG method and the UNIFAC method are made. Vapor-liquid equilibrium relationships of the quaternary reactive system producing tert-butylmethylether by use of methanol and tert-butylalcohol are also observed. and it is confirmed that the Wilson parameters resulting from the data of binary systems can be used to estimate the vapor-liquid equilibrium data for the quaternary reactive system of methanol-tert-butylalcohol-tert-butylmetherwater.