The invention discloses a testing method for the performance of a photocatalytic air-purifying material. The testing method comprises the following steps: preparing a sample piece of the photocatalytic air-purifying material and placing the prepared sample piece in an enclosed reaction chamber; irradiating the sample piece with a light source so as to realize pretreatment of the sample piece; introducing a target pollutant with a fixed concentration into the reaction chamber by using a partial pressure method and carrying out dark adsorption on the sample piece; and carrying out a photocatalytic degradation reaction and detecting concentration changes of the target pollutant, a degradation intermediate and a final degradation product, i.e., carbon dioxide, by using a gas chromatographic-mass spectrometric instrument. The testing method is rapid and highly efficient, has accurate and reliable testing results and high testing stability, can simultaneously characterize the adsorption performance and photocatalysis performance of the photocatalytic air-purifying material and the photocatalysis performance of material from the two aspects consisting of the concentration change of the target pollutant and the concentration change of the degradation intermediate, and is beneficial for objective and accurate characterization of the performance of the photocatalytic air-purifying material; thus, the method can promote extensive application of the photocatalytic air-purifying material.