Considering the shortcomings of low data rate,low response speed,high driving voltage,low electrical to optical efficiency and excessive power of the existing short range ultraviolet (UV) communication system based on low pressure mercury lamps,an improved short-range UV communication system based on deep UV LED is proposed. This system takes pulse position modulation (PPM) and adaptive maximum likelihood demodulation as the key technologies. Photomultiplier tube is used to detect the weak optical signal. The scheme is simulated and realized by field programmable gate array. The simulation and experiment results indicate that the data rate and electrical to optical efficiency of the proposed system are improved greatly,and system power and driving voltage are also decreased.