This study generated a standard tree-ring width chronology by using Pinus tabulaeformis samples collected in the Liupan Mountain area and calculated the correlativity between standard chronology and SPI series, which covers three time units of different sizes (i.e., monthly, semi-monthly, and 10 day) and eight time scales. The result of correlation analysis between STD and SPI in different time units showed that semi-monthly was more suitable than monthly and 10 day units for correlation analysis because the shorter units lead a more accurate correlation expression, whereas very short units diluted the significant correlations. In addition, the correlation analysis between STD and SPI with multiple time scales showed that the multi-time scale characteristics of SPI revealed different responses of the radial growth of Pinus tabulaeformis to multi-scales water conditions. Trees exhibited response mechanisms to different water conditions in different growth units: 1) under the situation of low temperature, precipitation undermined the trees' growth in the short term, but promoted it in the long term; 2) in the pre-growing season, water conditions in long term were more beneficial than in the short term; and 3) in the growing season, sufficient precipitation at all time scales was crucial to the radial growth of Pinus tabulaeformis.