Abstract: In order to testify the fact that the nano TiO₂ coating can be used to purify air and kill the bacteria within spacecraft, the nano-TiO₂ coating photocatalytic experiments are carried out within a 4 m³ sealed chamber which is made up of rectangular organic glass plates, the area of nano TiO₂ coating is 4 m² and the irradiating ultraviolet wavelength is 365 nm. Data processing adopts the method of clean air delivery rate (CADR). The experimental results indicate that the nano TiO₂ coating's purifying rate of the sulfur dioxide is 23.09%, that of the formaldehyde is 2.48% and the nitrogen dioxide 4.88% per minute. The antibacterial rate of Escherichia coli is 96%- 99% and the rate of Klebsiella pneumoniae is 92%-96%.