Objective  The purpose of the functional endoscopic sinus surgery(FESS) by two stages was to diminish hemorrhage and prevent confusing anatomic sign and blurring visual field during operation.Method  Twenty  seven cases of chronic sinusitis were operated on using “this” method by which the lesions in nasal cavity and sinus were treated in two stages and compared to 26 cases of chronic sinusitis by routine method.Result  In “two stages” group,bleeding was decreased,lens adhering and visual blurring was diminished.The mean blood loss was 153.7?ml,the mean operating time was 148.9 minutes,and the mean cleaning up of  rudimental diseased tissue was 5.6 times while that in controls was 196.2?ml, 177.4 minutes and   7.8   times,respectively.Conclusion  There is a great advantage in “two-stages” method,and it can be used as an effective measure in FESS.