Abstract: The section of cone-shaped nozzle air flow measurement device for clinker cooling fan is small for an oversea cement project, resulting in the unstable operation of PID loop for the cooling fan air volume, in order to meet the PID operation requirements and improve the sensitivity of the measurement device, the cone-shaped nozzle flow measurement device of cooling fan has been modified. This paper introduces the modification method and installation requirements of the cone-shaped nozzle flow measurement device, and the calculation method of the flow coefficient and the field calibration result. The differential pressure value reaches 373Pa after modification when the design air volume is 29 965 m3/h. The static pressure of the pipeline system is increased by 248Pa, and the sensitivity of the flow measurement device is improved, ensuring the stable and automatic adjustment of the PID loop.