To analyze the accumulation rule of pharmacodynamic substances of characteristic chemical constituents of Radix polygala in different growth years. FTIR was used to scan and analyze 12 batches of Radix polyphyllum with different growth years in Fenyang and Xinjiang of Shanxi Province. The infrared fingerprint of Radix polyphyllum was established, and the sequence of common peak rate and variation peak rate was analyzed. There were obvious common absorption peaks at 3 130, 2 920, 1 650, 1 540, 1 400, 1 260 and 1 050 cm-1. The characteristic absorption peaks of ethanol extract were in the range of 3 150～3 000, 2 950～2 920, 2 850, 1 740～1 710, 1 670～1 630, 1 540～1 520, 1 450～1 400, 1 100～1 050, 990, 530 cm-1. The number of absorption peaks increased with the increase of age. In the same year, there were differences in the number, shape and strength of absorption peaks near 3 380, 1 315, 1 060 and 990 cm-1 for P. polygonum, and the number, shape and strength of absorption peaks near 3 360 and 1 315 cm-1 for alcohol extract, and there was no characteristic absorption of P. polygonum in autumn. In terms of the accumulation of pharmacodynamic substances, the accumulation of pharmacodynamic substances in Fenyang and Xinjiang polygonum was larger in spring harvesting, and the accumulation of tenuifolin in fenyang polygonum, 3,6’-Disinapoylsucrose, and Polygalaxanthone Ⅲ increased with the growth of polygonum. The accumulation of 3,6’-Disinapoylsucrose increased firstly and then decreased, while the contents of Polygalaxanthone Ⅲ and some tenuifolin decreased with the increase of growth years. The common peak rates were 66.7%~100%, the variation peak rates were 0~63.6%, the common peak rates of alcohol extract were 66.7%~94.7%, and the variation peak rates were 0~30.0%. The common peak rate of the same period was high, and the peak rate between spring and autumn harvests was high. The common peak rate was high, and the accumulation of pharmacodynamic substances was similar to the increase in age, but there was no significant difference. The highest mutation peak rate was S-2-3 (picked in spring) and S-2-5 (picked in autumn), which was 63.6%. The two sequences were harvested in different seasons in different years, and the accumulation of pharmacodynamic substances differed greatly. The characteristic peaks of effective chemical components and the accumulation of pharmacodynamic substances of P. polygonum in different growth years can be analyzed and explored based on infrared spectroscopy and second derivative combined with double index sequence analysis, which can provide a reference for quality evaluation of Polygala tenuifolia.