Portable water flow velocity measuring instrument

A portable water flow velocity measuring instrument provided by the present invention comprises a frame seat, a hand-held assembly, a controller, a speed detection module, a power slide block assembly and a driving mechanism, the middle parts of the inner walls of the periphery of a tunnel pipe of the frame seat are respectively provided with a guide slide way, and a reducing sleeve is fixed at the center of the top of the tunnel pipe and is sleeved with a vertical pipe of the hand-held assembly. The power sliding block assembly comprises a sliding block and a cross block which are fixed together, the tail end of each supporting arm of the cross block is provided with a follower wheel through a pin shaft, and the follower wheels are installed in the corresponding guide sliding ways in a matched mode respectively. The driving mechanism is used for driving the sliding block to move, the speed detection module is used for monitoring the moving speed of the sliding block, and the water flow speed is determined by