Design and realization of tea component analyzer is presented based on Near-infrared (NIR) spectrometry. The discrete interference filters are used as NIR diffuse reflectance part. A white board is embedded into the rotatable sample cell. The samples and the white board are scanned in a fast and alternative way, which tests sample and the white board simultaneously, effectively simplifying the mechanism and accelerating the sample detection as well as improving the accuracy. InGaAs Detector, instrumental amplifiers and 24-bit A/D converters are used in photoelectric signal processing system. The computer completes the value determination of absorbency and tea component analysis with the data transferred from USB 2.0 interface. The relative error between this instrument and conventional chemical analysis is less than 5% by the experiments result.