The utility model relates to a flowmeter technical field, and disclose an annular space leakproofness detects U type flowmeter convenient to installation, including the outer tube, the outside protective sheath of the apparent middle part fixedly connected with of outer tube, the inner chamber fixed mounting of outer tube has well draft tube, the inner wall fixed mounting of outer tube has velocity of flow inductor, the one end of velocity of flow inductor extends to the inside of well draft tube, the equal fixed mounting of one end on two sides has the connecting block about the outer tube inner chamber. This annular space leakproofness detects U type flowmeter convenient to installation sets up outside protective sheath of outer tube and well draft tube through the utilization for can directly measure through both ends intercommunications, great simplification connectivity structure, simultaneously again very big improvement the leakproofness of this U type flowmeter, made things convenient for installing and use of this U type flowmeter, great improvement the device's practicality.