The invention discloses an organic gas detection device based on a guided-mode resonance principle. A miniature gas cavity and a guided-mode resonance light filter are combined for organic gas detection. The organic gas detection device comprises a light source, a polarizer, the miniature gas cavity, the guided-mode resonance light filter, a spectro-grating and a CCD (charge coupled device), and the miniature gas cavity is formed on the upper surface of the guided-mode resonance light filter. Light generated by the light source passes through the polarizer, then is vertically emitted to the guided-mode resonance light filter with the miniature gas cavity from top to bottom and is finally received by the CCD through a spectrum of the spectro-grating after emergence from the bottom of the guided-mode resonance light filter, so that organic gas detection is realized. The organic gas detection device based on the guided-mode resonance principle is simple in structure, accurate in distinguishing of organic gases less in refractive index difference and beneficial to realization of miniaturization.