The invention relates to a fluorescent quantitative detection device and method. An upper computer of the device directly interacts with a user and is in communication link with a mainboard, the mainboard controls and is connected with a mechanical drive device and a fluorescent detection module, and the mainboard realizes mechanical scanning mechanism of the fluorescent detection module by controlling the mechanical drive device, collects fluorescence signals collected by the fluorescent detection module and sends the signals to the upper computer for data processing. The method comprises steps as follows: firstly, when temperature is increased to detection temperature, the fluorescent detection module detects a sample from a first hole site to the final hole site in sequence through themechanical drive device and stores a fluorescence signal value of each hole site; secondly, the mechanical drive device transmits the fluorescent detection module to perform detection from the final hole site to the first hole site, and stores the fluorescence signal value of each hole site; the fluorescence signal value of each hole site is an average value of two data. By means of multi-point cycle collection and averaging, measurement errors are reduced, and accuracy of a test and consistency between holes are improved.