[Objective] To study the relationship between structure of anterior segment tissues and open angle(AA) in normal subjects.[Methods] A total of 211 eyes from 211 normal subjects were enrolled,whose anterior chambers and lens were scanned using anterior segment optical coherence tomography (AS-OCT).The measuring items included AA,anterior chamber depth (ACD),anterior chamber horizontal diameter (ACHD),anatomical anterior chamber depth (AACD),ciliary band length (CBL),iris thickness (IT),lens thickness (LT),lens position (LP) and lens anterior apex position (LAAP).The relationship between the 8 biometric parameters and AA was analyzed using linear correlation,respectively.[Results] The mean of AA was (40 ± 17)°,with (44 ± 18)° in male,and (37 ± 16)° in female.The difference of AA between male and female was statistically significant (t ＝ 2.893,P ＝ 0.004).There was significant correlation between AA and ACD (r ＝ 0.721,P ＝ 0.000),LT (r ＝ -0.545,P ＝ 0.000),CBL (r ＝ 0.615,P ＝ 0.000),LAAP (r ＝ -0.717,P ＝ 0.000),LP (r ＝ 0.557,P ＝ 0.000),and ACHD (r ＝ 0.175,P ＝ 0.011).There was no significant correlation between AA and AACD (r ＝ 0.130,P ＝ 0.059),IT (r ＝ 0.129,P ＝ 0.061).[Conclusion] The AA of females was narrower than that of males.In normal subjects,the most important factors which determine AA are the lens,the location of the peripheral iris and ciliary body.