Abstract: Masson's pine is the main raw material for production of ground pulp (GP) in China. Its high resin content causes resin trouble in pulping pr ocess. Treatment of ground pulp with lipase was investigated to reduce resin content of pulp. The optimum treatment conditions of pulp with lipase was researched and the effect of resin-removal was evaluated. The results indicated that the optimum treatment conditions were: pH value 6.0, temperature 70℃, pulp consistency 10%, treatment time 60 min, enzyme dosage 0.8 IU/g. Compared with the original pulp, resin content of the treated ground pulp with lipase under optimum condition decreased by 52.58% and strength of the treated pulp increased in varying degrees.