The invention discloses an automatic direction finding and adjusting method and system of a wireless network bridge. The automatic direction finding and adjusting system comprises an automatic control chip, a positioning module, an input module, local directive antennas, and an automatic alignment mechanical device, wherein the positioning module, the input module, and the local directive antennas are connected with a signal input terminal of the automatic control chip and the automatic alignment mechanical device is connected with a signal output terminal of the automatic control chip. And a signal output terminal of the automatic alignment mechanical device and the positioning module are connected with the local directive antennas. According to the invention, information of two directive antennas of the wireless network bridge is collected; coordinate points of the two antennas in three-dimension space are obtained and are connected to obtain a theoretical geometrical datum line; and then according to the theoretical geometrical datum line and measurement data of a small-angle area, the directive antennas are adjusted to be at the directions with the strongest signals, thereby completing direction finding and adjustment. The whole adjusting method is simple without any manual intervention; and automatic direction finding and construction of a wireless network bridge system can be completed automatically. The alignment precision is high and the speed is fast.