Considered the influence of enclosure heat conduction, solar radiation and internal heat source on indoor thermal environment, it is numerically simulated and experimentally tested cooling effect of wind energy on a wind-driven ventilation office building in Tianjin in transient season. Compared with experimental result, simulation result assumes good linear relationship, but the tested data deviated from the linearity and the obtaining heat per unit area is higher at the same indoor temperature than the simulation result. Both the radiation heat and the instability of actual wind speed and direction result in linear deviation. Theoretical obtaining heat subtracts the heat extracted by wind-driven ventilation, while not subtracted in experimental result, which revealed the cooing effect of wind energy for this office building.