The utility model discloses a safety valve in pipes, which comprises an upper connector, a safety valve body and a lower connector which are sequentially connected from the top to the bottom. The upper connector, the safety valve body and the lower connector commonly form a through main hollow structure. A piston assembly, a valve plate assembly and a first spring are sequentially arranged in the main hollow structure between an upper step and a lower step from the top to the bottom. A liquid injection channel is formed above the piston assembly in the main hollow structure, a bridge channel is arranged at the periphery of the piston assembly, and the valve assembly is sealed at the lower end of the bridge channel. The central liquid injection channel is formed at the upper end portion, the piston assembly is hydraulically pushed, the valve plate assembly is pushed by the piston assembly, and a production liquid lateral outlet channel is opened to enable production liquid to enter between a large diameter oil pipe and a small diameter oil pipe to form an oil extraction channel. In oil extraction, high temperature liquid circulates in the small diameter oil pipe to transfer heat to the production liquid through heat transfer, thereby enabling temperature of the production liquid to be higher than that of paraffin precipitation and achieving the purpose of completely clearing and preventing paraffin.