The invention discloses a device and a method for rapidly measuring carbon black concentration in laminar flow diffusion flames based on parallel light. The measuring device comprises a xenon lamp, a burner, a convex lens A, a pore diaphragm, an attenuation group, a light filter, a charge coupled device (CCD) camera and a computer, wherein the xenon lamp is capable of shooting parallel light, the burner, the convex lamp A, the pore diaphragm, the attenuation group and the light filter are arranged successively behind the xenon lamp, the CCD camera is arranged behind the light filter, and the computer is connected with the CCD camera. Wavelength of the light filter is within the visible wavelength range of the xenon lamp. According to the device and the method, the xenon lamp is used for shooting parallel light with uniform brightness, the parallel light passes through test flames, changes of parallel light intensity before and after the parallel light passes through the test flames are measured, planar carbon black particle extinction coefficients are obtained, and planar laminar flow flame carbon black concentration distribution can be obtained further. The device and the method have the advantages of being convenient and rapid to measure, low in device requirements, fast in speed, changeable in flames, good in repeatability and the like; the method and the device can be applied in both the mechanism research on carbon black and the online measurement of carbon black concentration.