The vacuum and oxygenous annealing effects on transmissivity,excitation,emission spectra and luminescence decay life time of the single crystal cadmium tungstate grown by Czochralski method are studied respectively,which indicate that oxygenous annealing is advantageous for increasing transmissivity,light yield,blue light emission proportion to a certain extent,and energy resolution of cadmium tungstate crystal. This may be caused by the oxygen vacuum reduced by oxygenous annealing and their absorption decrease in the range of 340～440 nm. Meanwhile,oxygenous annealing is advantageous for shortening luminescence decay life time and improving time resolution of cadmium tungstate.