The utility model belongs to the technical field of bridge engineering, particularly, relate to a stress test system under bridge structures prestressed component anchor. It includes prestressed component, ground tackle, anchor clamps, stopper, pressure sensor, hydraulic jack and prestress wire, the prestress wire has the multi beam, buries underground in the prestressed component, and its anchor end is equipped with anchor clamps, the ground tackle is fixed with all anchor clamps, and its right side is equipped with stopper, pressure sensor and hydraulic jack in proper order. Compared with the prior art, stress test system under bridge structures prestressed component anchor in the testing process, when the counter pull slightly was greater than original pre -applied force, small displacement took place with the prestress wire for anchor clamps, small displacement triggers stopper start -up work, control hydraulic jack oil pump stop work, the maximum pressure value that the test pressure sensor took notes is exactly a stress value under the anchor. Has the automation mechanized operation, advantage that analysis results is accurate.