1. A method for controlling a surveillance system, the surveillance system comprising a plurality of Pan-Tilt-Zoom (PTZ) cameras equipped with capturing direction adjustment capability, the method applied to a control circuit of the surveillance system, the method comprising: calculating monitoring regions of the plurality of PTZ cameras according to coordinates of the plurality of PTZ cameras, respectively, to generate space information of the monitoring regions, wherein any monitoring region of the monitoring regions comprises a union of a plurality of regions monitored by a corresponding PTZ camera within the plurality of PTZ cameras through capturing direction adjustment; automatically generating target patrol routes of the plurality of PTZ cameras according to the monitoring regions and according to a plurality of target points, wherein each target point within the plurality of the target points is generated and labeled on a corresponding position in an electronic map by capturing a predetermined region with a corresponding PTZ camera through capturing direction adjustment; and the step of automatically generating the target patrol routes comprises: determining whether the corresponding PTZ camera is equipped with capability to capture a specific target point within the plurality of target points according to space information of a monitoring region within the monitoring regions and according to a coordinate of the specific target point, in order to decide a target patrol route of the corresponding PTZ camera; and applying configurations corresponding to the target patrol routes to the plurality of PTZ cameras, respectively, to make capturing direction adjustment operations of the plurality of PTZ cameras correspond to the target patrol routes, respectively.