Abstract: Soil of four stages of rice （Oryza sativa L. ） transplanting were used as research objects to explore the differences of physical and chemical properties of rice soil at different sowing date. Daily data of air temperature and mud temperature were collected, and soil pH, nutrient content, mechanical composition and exchangeable base cations were measured. Through variance analysis and correlation analysis, the differences of physical and chemical properties of rice soil at different sowing date were discussed, and the soil comprehensive scores at different sowing date were calculated by principal component analysis. The results showed that soil nutrient content was from suitable to rich. The proportion of Ca²⁺ in the exchangeable base components was the highest, and the soil composition was mainly composed of silty grains. The content of clay grains of rice soil transplanted May 9 was the highest, and the corresponding fractal dimension was the largest. The results of correlation analysis showed that the correlation coefficient between K⁺ and Mg²⁺ was 0.953; Organic matter, total nitrogen and Na⁺ showed significant positive correlation; pH was significantly correlated with average temperature, while available potassium was significantly positively correlated with accumulated temperature; The clay content showed strong positive correlation with most indexes. Principal component analysis of various factors for different sowing date showed that the suitable date for rice transplanting was May 9.

Key words: sowing date of rice （Oryza sativa L. ）, soil, physical and chemical properties, central Guizhou province