A visible light waveband atmospheric transmissivity measuring method based on a single frame coloured image is disclosed. The method includes steps of (1) converting a single frame coloured RGB digital image of a targeted scene into an absolute radiation image according to absolute radiation calibration parameters of a color camera, (2) processing the absolute radiation image by combining an atmospheric scattering model and a dark channel prior statistical theory to obtain an atmospheric background light image in the absolute radiation image and a wide-waveband average atmospheric transmissivity corresponding to two-dimension scene dark channels, (3) refining the average atmospheric transmissivity by using guided filtering, and (4) obtaining the atmospheric transmissivity of a needed wavelength by combining the corresponding relationship of extinction coefficients of visible light with different wavebands and the wide-waveband average atmospheric transmissivity corresponding to two-dimension scene dark channels. The method is simple in devices, can achieve real-time high-precision low-cost measurement, and can be applied for long-distance targets and flying platforms.