Abstract: The present disclosure discloses a high precision channel flow measurement device and method based on a principle of multi-point head loss. A flow velocity of a designated position is acquired by using a flow measurement tube; the flow measurement tube is moved in a vertical direction through a convex sliding block and a motion guide pillar to measure the flow velocity at different measurement points on a measurement line; an overall flow measurement part is integrally ascended, that is, the motion guide pillar leaves a water body, in combination with a load bearing telescopic lifting frame; the overall flow measurement part integrally moves left and right in a longitudinal direction through a telescopic guide rod to reach a set position; the overall flow measurement part is integrally descended through the load bearing telescopic lifting frame, that is, the motion guide pillar enters the water body to acquire the flow velocity.