The invention relates to an online 
water quality monitoring device and method based on full spectra. The device comprises a pulse 
xenon lamp, a cleaning module, a spectrum measuring module and a 
control unit. One end of the cleaning module is connected with the pulse 
xenon lamp, the other end of the cleaning module is connected with the spectrum measuring module, the 
control unit controls the pulse 
xenon lamp to emit 
pulse light, controls the cleaning module to clean a measuring surface as needed and carry out light 
path switching, and controls the spectrum measuring module to read the 
light signal intensity of each waveband. According to the online 
water quality monitoring device and method based on full spectra, 
ultraviolet visible full waveband absorbing spectra are adopted for measuring the 
water pollution condition, factors such as COD, BOD, TOC, 
nitrate, 
nitrite, the 
turbidity and 
chromaticity can be measured, and the online 
water quality monitoring device and method based on full spectra have the advantages of being high in measuring precision, short in measuring time, large in number of monitoring factors, free of a 
reagent and secondary 
pollution and the like; the changing condition of 
water pollution is reflected in real time, and corresponding 
chemical models can be established according to ingredients of field water samples to meet the demands for measuring different water bodies.