An embodiment of the invention provides an X-band dual-polarization weather radar quantitative precipitation measurement method and an X-band dual-polarization weather radar quantitative precipitationmeasurement system. The X-band dual-polarization weather radar quantitative precipitation measurement method comprises the steps of: utilizing an X-band dual-polarization radar to obtain radar data in a detection range, and using a laser raindrop spectrograph to obtain an actually measured raindrop spectrum of a detection point; acquiring a radar reflectivity factor and an attenuation rate; acquiring an actually measured rainfall rate and a radar reflectivity factor true value of the detection point based on the actually measured raindrop spectrum, acquiring an attenuation rate true value ofthe detection point through T matrix scattering simulation, acquiring a rainfall function in the detection range through fitting the actually measured rainfall rate and the attenuation rate true value, and further acquiring a rainfall rate; inverting the rainfall rate by using the attenuation rate if the radar reflectivity factor is greater than a first set threshold value; and acquiring an attenuation rate function in the detection range through fitting the radar reflectivity factor true value and the attenuation rate true value is the radar reflectivity factor is not greater than the first set threshold value, and then acquiring a rainfall rate in the detection range based on the attenuation rate function. The X-band dual-polarization weather radar quantitative precipitation measurementmethod and the X-band dual-polarization weather radar quantitative precipitation measurement system can acquire more precise predicted rainfall rates.