Ultraviolet and visible spectrophotometer

The invention provides an ultraviolet and visible spectrophotometer which comprises a light source, a lens, an optical fiber, a collimating mirror, a shading cap, an integrating sphere and a spectrometer. The light emitting wavelength of the light source is within the range of 200 nm to 1000 nm. The light emitted by the light source passes through the lens and then enters from one end of the optical fiber, the other end of the optical fiber is provided with the collimating mirror, the shading cap is arranged between the collimating mirror and a sample to be detected, the light is transmitted by the optical fiber and then is emitted from the collimating mirror in parallel and enters the sample to be detected, and the light is emitted from the sample to be detected and received by the integrating sphere and transmitted to the spectrometer for analysis. The absorbance of a solid sample and a liquid sample can be measured, the shading cap can reduce the influence of ambient light on the instrument, a light path d