In this work, the vapor−liquid phase equilibrium (VLE) data of the 1octene hydration reaction system were investigated with the aim of providing a basis for carrying out the direct hydration of 1-octene to 2-octanol in reactive distillation due to the fact that the 1-octene hydration reaction route receives a strong limitation of the slow reaction rate catalyzed by known catalysts. In this work, experimental data of VLE were measured for four binary systems in the 1-octene hydration reaction system with 1,4dioxane and isophorone as cosolvents, respectively, namely, two binary systems with 1,4dioxane as a cosolvent (1-octene + 1,4-dioxane and 2-octanol + 1,4-dioxane) and two binary systems with isophorone as a cosolvent (1-octene + isophorone and 2-octanol + isophorone), the experimental data were subsequently correlated with two different activity coefficient models (NRTL and UNIQUAC) with good correlation results, and the binary interaction parameters of the two activity coefficient models were determined for the four systems.