The technique of incisional construction, the degree of automatic closure and the results of postoperative induced corneal astigmatism were reported in a series of 50 eyes with 5.5 mm sutureless incision for 6.0 mm PMMA intraocular lens (IOL) implantation. The patients ages ranged from 8 to 72 years. In this study, I-stage implantation was performed on 13 eyes and II-stage implantation, on 37 eyes. In this group, 19 aphakic eyes had had the histories of penetrating injuries and 1 to 3 times of operations. 15 aphakic eyes had had histories of senile cataract extractions, 14 eyes were congenital cataracts and another 2 eyes were other kinds. The surgical maneuvers included an external scleral frown incision 5 mm in chord length, a scleral-tunnel dissection and a corneal internal valve incision into the corneal limbus for 1 mm and keeping horizontally 6.0 mm in width. All the implantations were smooth, incisions closed watertightly without leakage or shallow anterior chamber. The means value of induced corneal astigmatism was -0.16(0.71)D with a range of +1.00 to -1.50 D. The complications were less than that of sutured operations. The results suggest that sutureless incision be safe, reliable, self-closed tightly, less induced astigmatism and could be a better kind of incision for standard IOL implantation.