The invention provides a short wavelength deep ultraviolet laser output device comprising a first fundamental frequency source, a frequency doubling crystal, a KBBF-PCD device, a polarization apparatus, a high reflective mirror and a second fundamental frequency source, wherein the first fundamental frequency source is used for generating first fundamental frequency light; the frequency doubling crystal generates a frequency doubling light output during a non-linear process; the KBBF-PCD device is used for outputting quadruplicated frequency light; the polarization apparatus is used for outputting the quadruplicated frequency light after the polarization light of the quadruplicated frequency light is rotated for 45 degrees; the high reflective mirror is used for returning the quadruplicated frequency light after being rotated for 45 degrees back to the polarization apparatus, and the quadruplicated frequency light is returned back to the KBBF-PCD device after the polarization direction is further rotated for 45 degrees; and the second fundamental frequency source is used for generating second fundamental frequency light, and performing sum frequency on the second fundamental frequency light and the quadruplicated frequency light further entering the KBBF-PCD device, and generating a short wavelength deep ultraviolet laser output. According to the device provided by the invention, the short wavelength deep ultraviolet laser output is achieved by using the single KBBF-PCD device; the required fundamental frequency source is low in requirement, small in size, low in cost and high in stability.