Abstract: Objective To explore the difference in intensities of ocular exposure to ultraviolet (UV) irradiance in diurnal distribution and at different solar elevation angle (SEA) between Xichang and Shaoxing city at different altitude.Methods A self-designed rotating manikin and dual-detector spectrometer were used to monitor the intensity of ocular exposure to UV irradiation under clear sky in Xichang and Shaoxing city.Monitoring data were processed and analyzed with AvaSoft 7.4 USB2 software and OriginPro 8 software.Results In maximum exposure,both the ocular ultraviolet radiation A (UVA) and ultraviolet radiation B (UVB) diurnal variations exhibited bimodal distribution in Xichang and Shaoxing city;the maximum values of UVA were 2 181.91μW/cm² and 2 003.6μW/cm²;and those of UVB were 117.2 μW/cm² and 72 μW/cm²,respectively.As for the ratio of ocular to ambient exposure,the study results revealed that the ratio was almost the same in two areas for UVA maximum exposure (0.79 and 0.80);but for the UVB maximum exposure,the exposure ratio of Xichang is higher than that of Shaoxing (0.68 vs.0.55).Conclusion The maximum ocular UVA and UVB exposure exhibit bimodal diurnal distribution in Xichang and Shaoxing city.Under the same solar elevation angle,the intensity of ocular exposure to UVB irradiance in Xichang is higher than that in Shaoxing,the ratio of ocular to ambient UVB exposure in Xichang was higher than that in Shaoxing.