In this study, hydrodynamic behavior of four-sided wind tower attached to parlor and courtyard of a scaled model form existing historical house with wind incident angel as variable was numerically investigated. Hazire-ei house wind tower, which has six channels with rectangular cross section, integrated with parlor and courtyard is considered among the most typical ones in the vernacular architecture of Yazd city. This article seeks to investigate the performance of four-sided wind tower regarding suction and supply amount of air and the way it was used as a vernacular solution for natural ventilation in order to provide engineers with design guidelines for contemporary use. Numerical study was conducted on a 1:25 scaled model and for 13 wind incident angels with 15 degrees intervals and interested parameters are mass flow rate and flow direction in each channel. A structured mesh was generated and ANSYS Fluent software was used for numerical simulation. Numerical modeling results were validated against experimental tests conducted on the same scaled model and good agreement was observed. Results indicate that in 68.5% of incident angels, four-sided wind tower acts as sucking the air out of building and in other incident angels with approximately equal amount of supply and extract rate, it operates as an air exchange unit. Accordingly it can be concluded that putting aside stack effects, four-sided wind towers in dry regions of Iran are mostly employed for heat dissipation elements rather than inducing outdoor cool breezes.