The invention discloses a focus-controllable super-resolution microscopic device based on a spherical micro-nano droplet lens, comprising: a laser, a mirror, a first lens group, a dichromatic mirror, a linear polarizer, a microscopic objective lens, a packaging box, Spherical micro-nano droplet lens, micro-flow tube, micro-displacement stage, sample stage, second lens group, imaging device, computer control system. The computer control system controls the microfluidic tube to release or absorb a certain volume of liquid droplets in the packaging box, and then regulates the radius of the spherical micro-nano liquid droplet lens to realize zooming of the spherical micro-nano liquid droplet lens. Aiming at the disadvantages of the uncontrollable focusing characteristics of the existing micro-nano structure, the present invention proposes a focus-controllable super-resolution microscopic device based on a spherical micro-nano droplet lens, which uses the spherical micro-nano droplet lens to generate photon nanojet , by adjusting the focusing characteristics of the spherical micro-nano droplet lens, the scanning of the sample at different depths can be realized without mechanical structure vibration; and it can be combined with the micro-stage to control the sample stage to realize the horizontal scanning, and complete the three-dimensional ultra-scanning of the sample. Resolution microscopy imaging.