【Objective】The role of biochar-based organic fertilizers in improving soil fertility and health, in general, has gained a lot of attention in recent times. It is the premise of scientific fertilization to make clear which planting areas are suitable for applying biochar-based organic fertilizer and which areas are not.【Method】Based on 2 059 soil samples in Bijie tobacco planting area of Guizhou Province, this study analyzed the distribution characteristics of soil pH and the spatial changes of soil properties, such as organic matter, available calcium, available magnesium, clay content and cation exchange capacity(CEC). Based on the overall consideration of soil pH and soil acid-base buffer potential, the suitability grade of biochar-based organic fertilizer application in the Bijie tobacco planting area was obtained.【Result】The results showed that the average pH value of all sampling points in Bijie tobacco growing area was 6.5, which was weakly acidic. The average pH values of Dafang County, Qixingguan District and Weining County were only 6.2, 6.3 and 6.3, respectively, while those of Zhijin County, Jinsha County and Qianxi County were more than 7.0. The contents of organic matter, available calcium and magnesium, clay and CEC in tobacco planting soils in different counties were different, which led to the differences of soil acid-base buffer index between different counties. In all counties, the comprehensive index of acid buffer in Dafang and Weining was 0.96, while that in Zhijin was 1.23. Generally, there was a positive correlation between the pH value and the buffering potential of each parent rock soil type. The pH value of sandstone coarse bone soil and yellow soil was lower, and the value of the acid-base buffering potential index was also smaller. Also, the value of carbonate limestone soil with higher pH value was higher than that of other soil types. The suitability grade of biochar-based organic fertilizer calculated by pH value and acid-base buffer composite index showed that except for the purple soil of sand shale, the soil types derived from sandstone and sand shale were the most suitable application grade, and it was very necessary to apply a biochar-based organic fertilizer to improve soil pH value in these soil types. Carbonate and calcareous soils were not suitable for the application, which indicates that biochar-based organic fertilizer is not suitable for the two soil types without changing the current soil pH and acid-base buffer potential. The remaining soil types from other parent rocks belong to the suboptimal grade, and a certain amount of biochar-based organic fertilizer should be applied to these soil types to moderately increase the pH value, to keep the soil pH in a better state.【Conclusion】From the township level, the town numbers of key application, general application, and unsuitable application grades were 82, 144, and 32 respectively. The key application towns of biochar-based organic fertilizer were mainly concentrated in Weining County, Zhijin County, and Hezhang County. The towns with general application grade were more, and most of them were distributed in Dafang County and Qixingguan District. The unsuitable application towns for biochar-based organic fertilizer are mainly concentrated in Qianxi County and Jinsha County. This study fully considered the effects of soil pH value and acid-base buffer potential on the suitability of biochar-based organic fertilizer, and identified the key application, general application and unsuitable application towns in the Bijie tobacco planting area. This study provides a scientific basis for the accurate application of biochar-based organic fertilizer in the Bijie tobacco planting area and also enriches the research connotation of soil management division in the tobacco planting area.