Using a kind of compound solvent as denitrification agent to remove the basic nitrogen of CGO .Different process conditions including reaction temperature, denitrification agent to CGO mass ratio and reaction time on the effect of basic nitrogen remove rate and the light oil yield were studied．The experimental results show that the oil yield was 94.23% , and the basic nitrogen remove rate reached to 85.62% under the conditions of the reaction temperature 72 ℃ , the solvent to oil mass ratio 2.5%, the stirring speed 300 r/min , the reaction time 30 min and the settling time 15 min，which is the best reaction condition.