Geostatistical methods were used to systematically analyze the spatio-temporal variation characteristics and spatial distribution patterns of pH and Olsen-P in tobacco growing soil in Nanjian county，a typical county of Dali prefecture，Yunnan province，during 1982，2012，2018 and 2022，which could provide scientific basis for nutrient management and balanced fertilization in tobacco fields in this area. The results showed that the soil pH showed a decreasing trend during the 40 years from 1982 to 2022，with an average annual decrease rate of 0.014 units，and the soil pH was strongly spatially autocorrelated in all four periods. The proportion of pH grade III tobacco field area was decreased，including a significant decrease in the northeast and southwest，and the proportion in grade I and II was increased，but the proportion of grade III area was still the highest. The soil Olsen-P content was increased first and then decreased during the past 40 years，with an average annual increase rate of 0.34 mg/kg during 1982-2012，and the average annual decrease rate was 0.76 mg/kg during 2012-2022. The Olsen-P showed strong spatial autocorrelation in 1982，2018 and 2022，and structural factors played a dominant role，while the Olsen-P showed moderate spatial autocorrelation(44.1%)in 2012，which was affected by both structural factors and human factors..The highest proportion of Olsen-P grade area was decreased from grade Ⅲ to grade Ⅱ from 1982 to 2022，and the low content areas were concentrated in Leqiu town，the northeast of Baohua town and part area of Xiaowandong town. During the 40 years，the soil pH showed a decreasing trend，and the pH was generally low in the west of the county. The Olsen-P was increased first and then decreased，with a low content in the west and a high content in the northeast. The soil acidification should be prevented and controlled in Nanjian county as a whole，and the application of phosphorus fertilizer should be increased appropriately. The management measures of organic and inorganic combined application should be promoted to improve the soil fertility of tobacco fields.