By means of measurement of creep properties and microstructure observation, the creep behaviors of a single crystal nickel-based superalloy containing 4.2%Re were investigated. Results show that after fully heat treated, the microstructure of the alloy consists of the cubical γ￠ phase embedded in the γ matrix as coherent form. In the range of the applied stresses and test temperatures, compared to the free-Re superalloy, the superalloy with 4.2% Re possesses a better creep resistance and longer creep lifetime, and the creep activation energy and stress exponent of the alloy during steady state creep have been calculated. By means of analyzing the dislocation climbing over the rafted γ￠ phase and the factors effecting on strain rates of the alloy, the deformation mechanism of the alloy during steady state creep was investigated. Thereinto, dissolving of Re into the alloy matrix may hinder the dislocations movement and reduce the strain rate of the alloy, which is thought to be the main reason for the alloy possessing lower strain rate and longer creep lifetime.