The invention discloses a water sealing device applied to hydraulic fracture experiment under high-temperature and high-pressure condition. The water sealing device comprises a hole sealing nut, a 
metal water pipe, a locking nut, 
metal washers and wedge-shaped sealing red 
copper rings, wherein the wedge-shaped sealing red 
copper rings sleeve the 
metal water pipe which extends into 
drill hole inside a 
rock sample, are partitioned by the metal washers, and each wedge-shaped sealing red 
copper ring is formed by oppositely buckling two copper seals with slopes; the inner surface and the outer surface of each wedge-shaped sealing red copper ring are vertical surfaces; the wedge-shaped sealing red copper rings expand in a tester under the condition that the 
maximum temperature can reach 600 DEG C; the inner vertical surfaces and the outer vertical surfaces are used for pressing the metal 
water pipe and rock hole wall respectively, so that the initial hole sealing is implemented; the wedge-shaped sealing red copper rings are pressed and deformed to expand in the process of applying load to the 
rock sample by the tester; the outer vertical surfaces are on 
close contact with the hole wall of the 
rock sample; the inner vertical surface is in 
close contact with the metal water 
pipe, so that the high-pressure water sealing in the experiment process is implemented. According to the water sealing device, the wedge-shaped sealing red copper rings are additionally arranged outside the metal water 
pipe, so that the water sealing under the high-temperature, high-load and high-pressure condition is realized; the device is simple in structure, reliable in performance and high in stability, and is applied to the hydraulic fracture experiment of the rock under the high-temperature and high-pressure condition.