An integrated window-opening side-drilling tool comprises a milling cone, the inclined iron of an inclination guider and a set anchoring device, which are sequentially connected, wherein a liquid guide pipe is arranged in the inclined iron of the inclination guider. The lower part of the milling cone is provided with an annular groove along a circumference direction, a positioning block is arranged on the inclined iron of the inclination guider corresponding to the annular groove; an arc clamping edge is arranged on the positioning block, and a positioning bolt is arranged between an upper end of the inclined iron of the inclination guide and the milling cone. The integrated window-opening side-drilling tool is characterized in that: a milling cone inner bore is formed by a connection screw hole at center of the upper part of the milling cone, a center bore at the center of the lower part of the milling cone and a circulation channel which connects the connection screw hole and the center bore, a tap hole is arranged at the lower end of the connection screw hole along the milling cone radial direction, a cone set clamping edge is arranged at the lower part of the connection screw hole, and the tool is also provided with a set ball cooperated with the set clamping edge. Through the tap hole, the excitement pressure generated by drilling fluid in the tool inner cavity during the integrated window-opening side-drilling tool going down process can be released, thus mis-set by the set anchoring device is avoided.