Abstract: Objective To evaluate the effect of submaximal exercise on intraocular pressure of civil aviation pilots. Methods Seventyone pilots of an airline who had undergone physical examination from July 2015 to June 2016 were enrolled in our study. Their intraocular pressure (IOP) was measured by a hand-held tonometer. Measurements were taken before submaximal exercise and at 0 min, 30 min, 45 min, 60 min after submaximal exercise. Results IOPs before submaximal exercise, at 0 min, 30 min, 45 min, 60 min after submaximal exercise were (15.35±3.04) mmHg (1 mmHg=0.133 kPa), (12.90±2.61) mmHg, (14.00±2.90) mmHg, (14.62±2.96) mmHg, (15.26±3.01) mmHg in right eyes, and (15.23±3.12) mmHg, (12.81±2.64) mmHg, (13.92±2.92) mmHg, (14.59±3.05) mmHg, (15.22±3.10) mmHg in left eyes. IOP decreases were 2.45 mmHg (15.96%) in right eye, and 2.42 mmHg(15.89%) in left eye at 0 min after submaximal exercise, which were significantly higher than those at other time points. IOPs of both right eye and left eye were lower at 30 min and 45 min after submaximal exercise when compared with those before submaximal exercise (P< 0.05, respectively), and it returned to normal (before submaximal exercise) at 60 min after submaximal exercise. Conclusion Submaximal exercise can decrease IOP of pilots. When the exercise intensity reaches submaximal level, IOP decreases most significantly, and the influence lasts about 45 min to 60 min.