The invention discloses a prestressed reinforcement rock-socketed cast-in-place pile which comprises a steel casing of the cast-in-place pile and a plurality of reinforcing steel bars, wherein the plurality of reinforcing steel bars are respectively sleeved in a steel sleeve; the lower ends of the reinforcing steel bars extend out of a closure plate; the upper ends of the reinforcing steel bars are fixedly connected with the lower side of an anchoring plate respectively; a plurality of transverse connecting pipes are communicated with the lower ends of the reinforcing steel bars respectively; the plurality of reinforcing steel bars extending out of the anchoring plate respectively are stretched one by one to form prestressed reinforcements, and the steel sleeve is fully filled with cement paste. The invention also discloses a construction method of the prestressed reinforcement rock-socketed cast-in-place pile. The method comprises the following steps of 1, preparation before embedding of the reinforcing steel bars; 2, embedding of the reinforcing steel bars; 3, concrete pouring; 4, stretching of the prestressed reinforcements; 5, filling of the steel sleeve 6 by the cement paste; 6, concrete pouring and sealing. Due to the adoption of the prestressed reinforcement rock-socketed cast-in-place pile construction method, the bending resistance of the rock-socketed cast-in-place pile can be greatly enhanced by applying prestress to the high-tensile reinforcing steel bars, the diameter of the rock-socketed cast-in-place pile is reduced, and the construction cost is lowered.