Wind tunnel tests were conducted to study the correlation of the internal pressure of opening buildings and the external pressure around the orifice， as well as the effects of turbulence intensity， wind direction and opening ratio on the internal pressures. In addition， the wind tunnel test results were compared with national and international codes， and advantages and disadvantages of these codes were also analyzed. It is found that the internal pressure of the opening building is highly synchronous with the external pressure around the orifice in the time history， but it is quite different in the power spectrum at oblique wind angles. The mean internal pressure responses increase with the increase in turbulence intensity and opening ratio. Both the Chinese load code and the American ASCE7-16 greatly underestimated the internal pressure coefficient， while the internal pressure coefficients proposed by AS/NZS 1170.2：2011 are in good agreement with the wind tunnel test results.