Force tests of tall buildings with openings at its two levels of 0.5H and 0.85H were conducted in the atmospheric boundary layer wind tunnel, and then the wind-induced base forces were obtained with different parameters, such as the dimension, height, location and amount of the openings. The influences on the wind effects of tall buildings with different openings were investigated on the basis of the basement bending moment coefficients and basement first mode aerodynamic force spectrums. The results show that the basement mean bending moment can be reduced efficiently by the opening at along-wind direction, the reduction is more evident for the opening at higher location than that at lower location, and the larger opening also plays more effectual roles for the reduction of basement mean bending moment. The basement mean bending moment at across-wind direction is small, and the value increases in case of large opening, contrary to that for small opening. Furthermore, both of the openings at along-wind and at across-wind directions have influence on the basement fluctuating bending moment. The narrow band frequency with a peak value of 0.12, which is close to the reduced frequency of the vortex shedding, is found for both the cases of large opening and small opening. The difference of power spectrum value is more remarkable in lower-frequency section than that in high-frequency section for different cases.