Soil microorganisms are among the most active components of terrestrial ecosystems, as promoters of energy and nutrient recycling of ecosystems. They are also recognized as early warning and sensitive indicators of soil ecosystems. Here, we conducted a field study to analyze the soil microbial biomass in the Karst gorge region in Southwestern China. The study was conducted over a typical area of sloping farmland in the Karst gorge region. The total study area of (300 × 200) m² was divided into (20 × 20) m² grids using an Electronic Total Station, yielding 212 sample points. We examined the spatial patterns of soil microbial biomass using geo-statistical and statistical methods. The spatial patterns of soil microbial biomass and their main influencing factors were revealed by grid sampling methods, combining classical statistics and geostatistics methods. The soil microbial biomasses of carbon (C_mic) and phosphorus (P_mic) and their ratio (C_mic/N_mic) were moderately high in this Karst region of Southwestern China. The average soil microbial biomasses of carbon (MBC), nitrogen (MBN), and phosphorus (MBP) were 75.62 mg/kg, 25.23 mg/kg and 24.06 mg/kg, respectively. The ratios of MBC to MBN (MBC/MBN) and MBC to MBP (MBC/MBP) were 3.87 and 5.61, respectively. The variation coefficients of the biomasses ranged from 14.193 to 182.756%, while those of the ratios ranged from 14.192% to 114.512%. The values of all five variables were moderately high and widely varying. The smallest Moran's I result for MBC, MBN, MBP, MBC/MBN and MBC/MBP was -0.0965, -0.0556, -0.0913, -0.0682 and -0.0654, respectively, suggesting strong spatial heterogeneity of the soil microbial biomass. The MBC, MBN, MBP, and MBC/MBN were best fitted to an exponential model, while the MBC/MBP was consistent with a spherical model. The RSS values were very small, indicating good model fitting. The nugget (C₀) was low (0.0245-13.4) and all C₀/(C₀+C) values were less than 25%, indicating that the soil microbial biomasses are strongly autocorrelated over the study region, and that their spatial patterns are influenced by structural factors. These spatial patterns varied over a small range (30.9-60.6 m). The ranges of the MBN and MBP patterns were similar (40.5 m and 30.9 m, respectively), and were smaller than that of MBC (60.6 m). On Kriging contour maps, the regions of high MBC occupied the middle and upper parts of the slope, while high MBN was found on the upper parts and foot of the slope. The MBP displayed a clear spatial distribution pattern with high values at the foot of the slope. The MBC/MBN pattern was characterized by larger patches with an alleviate variation, while that of MBC/MBP was unobvious and was fragmented into many patches. Numerous factors influence the spatial patterns of soil microbial biomasses in the sloped Karst gorge region. Soil depth, pH, and available nitrogen are the main influencers of carbon and nitrogen biomass. In addition to the small-scale spatial distributional patterns of microbial biomass in the study region, different spatial patterns were observed in the soil microbial variables. Therefore, by adopting appropriate statistical and analytical techniques, we can elucidate the extent and distribution of microbial activity in soils.