OBJECTIVE To evaluate the biocompatibility of F-heparin surface modified IOLs. METHODS 13 monkeys were divided into 3 groups, and implanted with different surface modified and non-modified IOLs into their eyes. All of the eyes were examined by slitlamp microscope and Schiötz tonometer at postoperative 15, 30, 60, 90 and 180 days. Postoperatively, at different periods the aqueous was aspirated from the anterior chamber to calculate cells. RESULTS F-heparin surface modified IOLs induced milder inflammatory reaction and less dense posterior capsula opacification (PCO) than non-modified IOLs. CONCLUSION F-heparin surface modified IOL has a better biocompatibility.