The invention discloses a cell capture and fluorescence enhancement device and method based on a biological lens. The device comprises a laser device, a photoelectric detector, an oscilloscope, an optical fiber coupler, a spectrograph, an optical coupling part, a microscope, an objective lens, a computer, an optical fiber adjusting rack, capillary glass tubes, an optical probe, a suspension, an objective table and a glass slide. The method includes following steps: S1, preparing the optical fiber probe for capturing an experimental object and a detection signal; S2, preparing a bacterial suspension; S3, preparing target capture cells; S4, preparing a biological lens suspension. Nano photon jet flow having stronger focusing property is utilized to excite stronger fluorescence of upconversion nano light particles, so that the light-emitting efficiency of the device is improved by two magnitude orders.