Flow fluorescence collecting optical system

The invention discloses a flow fluorescence collecting optical system. The flow fluorescence collecting optical system comprises a fluorescence collecting lens, a micro beam splitting lens, a plurality of achromatism collimating lenses, a plurality of multicolor lens light filter sets, a plurality of focusing lenses and a plurality of detectors, wherein the fluorescence collecting lens is used for amplifying fluorescence generated by exciting a sample by virtue of a plurality of different laser beams as a plurality of fluorescence image points with gaps which are formed between the fluorescence image points; the fluorescence image points formed by amplification of the fluorescence collecting lens irradiates the micro beam splitting lens; the micro beam splitting lens is used for splitting light and removing stray light of the plurality of fluorescence image points; all the beams of fluorescence image points split by the micro beam splitting lens are processed by achromatism by virtue of at least one achromatism collimating lens; all the beams of fluorescence image points processed by achromatism are filtered by the multicolor lens light filter sets; all the beams of fluorescence image points filtered by the multicolor lens light filter sets are focued to the detectors by virtue of the focusing lens. The flow fluorescence collecting optical system is relatively low in cost, compact in structure, easy to mount and debug and high in measurement accuracy.