Solar eclipses cause corresponding impacts on the earth’s solar radiation, meteorology and human activities. A Solar eclipse occurred on June 21(summer solstice), 2020, in Tibet, the maximum magnitude of the annular eclipse was reached 0.995 in Ngari, and the maximum magnitude of 0.953 for the partial eclipse in Lhasa, Tibet. The eclipses for both locations occurred around the local noons. We, by taking the rare opportunity for appearing the solar eclipse, observed the solar spectra, global solar irradiance and solar UV radiation measured by the RAMSES solar spectrometers made in Germany, the CMP11global solar radiometers by Holland and the NILU-UV solar ultraviolet detectors made in Norway, respectively during the solar eclipse in Tibet. The observations show that the annular eclipse lasted about 3 hours 27 minutes. Around the local noon (Beijing time 14:41) in Ngari. The eclipse in Lhasa was 26 minutes behind Ngari and lasted about 3 minutes and 28 seconds shorter than Ngari. The observation showed that the peak value of strongest monochromatic (476.6 nm) light for Ngari’s spectra decreased sharply from 1 669.234 mW·m^-2·nm^-1 at the first contact phase (13:01 min) to 61.936 mW·m^-2·nm^-1 at the maximum phase (14:44 min), with a loss of about 96.0%. Simultaneously, the global solar irradiance decreased from 1 221.217 to 56.086 W·m^-2, and the loss was about 95.4% for Ngari. The peak value of the strongest monochromatic (476.6 nm) light during the solar eclipse in Lhasa decreased from 1 563.876 mW·m^-2·nm^-1 at the first contact phase (13:27) to 26.391 mW·m^-2·nm^-1 at the maximum phase of the eclipse (15:13), the deficit was about 98.3%, the global solar irradiance decreased from 1 605.663 to 28.169 W·m^-2 for the above corresponding time, and the net loss was about 98.2% too. We observed that the dose rates for solar UVB in Lhasa were also decreased about 98.5% for the value of 60.8 W·m^-2 at the first contact phase to 0.9 W·m^-2 at the maximum phase of the eclipse. The current solar eclipse caused more than 95% energy loss to Tibet’s surface solar radiation intensity.