The large water flow standard facility is the core device for carrying out large pipe diameter flow meter test and ensuring the accuracy and reliability of traceability and transmission of large water flow value, and the diverter is the most important component which affects the accuracy and reliability of the measurement results. Aiming at the limitations of the existing facilities for large water flow, such as difficult stability assurance, large reversing error, poor dimensional adaptability of the tested instrument and low test efficiency, a set of large diameter water flow standard facility with high accuracy, high velocity and a new reversing system were designed and developed. The facility has three principles of static mass method, volume method and standard meter method at the same time, and the maximum test pipe diameter is DN1000, the maximum operating flow rate is 10 000 m3/h, the local maximum flow velocity can reach 10 m/s, the overall uncertainty is better than 02% (k=2). The law of liquid quality change during the reversing process in the static mass method large flow standard facility was analyzed, and the relation model between reverse flow error and timing error is established, and finally the uncertainty evaluation test of this new type of diverter was carried out, the results show that the timing uncertainty is better than 883×10-6 and the total uncertainty of measurement time is better than 924×10-6, and the magnitude is very small, so the performance of the diverter is excellent.