The invention discloses a high temperature material hose pipe, a flow detection system and a coal pyrolysis system. The high temperature material hose pipe comprises a pipe cylinder (1), a weighing valve plate (2) which is arranged in a pipe barrel and is connected to an outwardly extended rotating shaft for weighing, a weighing driver (6) which is used for overturning the weighing valve plate by means of the rotating shaft for weighing between a weighing position and a flow passage position, and a weighing device which is arranged outside the pipe cylinder and is connected to the rotating shaft for weighing in order to weigh the high temperature material which is accumulated on the valve plate. In the flow passage position, the high temperature material flows forward through the pipe cylinder; in the weighing position, the weighing valve plate plugs the pipe cylinder so as to accumulate the high temperature material on the weighing valve plate. The flow detection system comprises a first measuring branch pipe and a second measuring branch pipe which are parallelly arranged, a material blocking plate (14) is arranged at the position of a top bifurcated pipe, so that material feeding can be switched between the two branch pipes. Continuous detection of flow of high temperature materials in the hose pipe can be realized with measuring accuracy and high safety, and continuity of process is not influenced.