Abstract: In the petroleum refining industry， the process for alkylation of isobutane with butene is an important approach to produce a high octane gasoline blend stock. In published literature, however, it is difficult to find out all the thermodynamic data for the alkylation. In this paper, thermodynamic calculation and analysis on the alkylation has been carried out in detail. The thermodynamic data on the alkylation including enthalpy ΔHt, Gibbs energy ΔGt and equilibrium constant of reaction at different temperature have been calculated. The affection of temperature, pressure and inert material on the thermodynamic equilibrium of the reaction has been discussed.