Objective: To research the change of cornea astigmatism after combined cataract phacoemulsification and Callisto Eye-assisted arcuate keratotomy and to assess the effectiveness and safety of this surgery for improving patients' uncorrected visual acuity. Methods: Prospective interventional non-randomized controlled study. Consecutive cataract patients with cornea astigmatism greater than 0.75 D were recruited at the southern part of Beijing Tongren Hospital, Capital Medical University and Beijing Tongren Eye Center, between October 2017 and March 2018, and were divided into the experimental group and the controlled group. In the experimental group the patients are further divided into three subgroups of A(0.75-1.24 D), B(1.25-1.74 D) and C(≥1.75 D) according to the degrees of their cornea astigmatism before surgery. The combined cataract phacoemulsification and Callisto Eye-assisted arcuate keratotomy were performed for the experimental group with the depth and length of the corneal arcuate incision differing in subgroups, while only cataract phacoemulsification was performed for the control group. The complications on and after the surgery were observed and the change of cornea astigmatism and uncorrected visual acuity in three months after surgery were recorded. Independent sample t test was used for statistical analysis. Results: A total of 108 patients (108 eyes) were enrolled, including 46 males and 62 females, the age was (68±11) years old.The experimental group included 76 eyes of 76 patients (subgroup A 38 eyes, subgroup B 18 eyes, subgroup C 20 eyes). The controlled group included 32 eyes of 32 patients. The preoperative cornea astigmatism and postoperative cornea astigmatism of the experimental group are (1.54±0.90) D and 0.62 (0.36-0.95) D. The change of cornea astigmatism of the experimental group is (1.15±0.58) D. The index of correction and flattening are 0.97±0.20 and 0.61±0.31 respectively, the error of axial deviation is 9.55°±5.22°. The index of success is 0.51±0.36. In the experimental group, subgroup C has the highest correction efficiency of corneal astigmatism (axial deviation error 8.07°±3.13°, flattening index 0.72±0.31) which is followed by subgroup B, and subgroup A ranked the last one (axial deviation error 10.27°±6.47°, flattening index 0.42±0.30).The uncorrected distance visual acuity (logarithm of the minimum angle of resolution) of the experimental group and the control group are significantly different (0.15±0.12 vs. 0.24±0.17, t=-4.129, P<0.01). None of the patients recruited have complications including poor wound healing and cornea penetration and cornea edema and cystoid macular edema on or after the surgery. Conclusions: Combined cataract phacoemulsification and Callisto Eye-assisted arcuate keratotomy are of favorable effect on improving the uncorrected visual acuity and have relatively good accuracy and predictability on the correction of cornea astigmatism. It is a safe surgery with considerable efficency. (Chin J Ophthalmol, 2019, 55: 502-508).