Abstract: Using X-band phased array dual-polarization weather radar data and ground observation data, three short-term heavy precipitation processes in Chengdu were analyzed. The Z_H parameter was used to establish a short-term heavy precipitation event warning index, and the availability of this index in short-term heavy precipitation forecasting and early warning was preliminarily explored. The results show that: (1) There were obvious low-center-of-mass echo structures in the three precipitation processes, and the greater the rainfall intensity was, the stronger the echo above the melting layer was, the greater the Z_DR intensity was, and the higher the positive Z_DR could reach (close to the melting layer). (2) The maximum value of the echo above the strong precipitation is more than 47 dBZ within 1 hour before the strong precipitation, which can be used as the early warning threshold of the local short-term heavy precipitation event, and can predict the occurrence of short-term heavy precipitation in advance to a certain extent. It has guiding significance for the short-term and imminent forecast and early warning of short-term heavy precipitation in Chengdu.