[Objectives]  To investigate the influence of soil characteristics on population of digger bees Andrena camellia Wu in a Karst region in Wenshan, Yunnan province. [Methods]  We selected two types of tea-oil camellia orchards in Yichun, Jiangxi province，one type having good nesting soils (NS) for digger bees and another without good nesting soils (NNS). We also selected two types of orchards in the Karst region of Wenshan, Yunnan, one type called peak cluster (PC) and another called depression area (DA). Soil penetration resistance, bulk density, water content, temperature, soil particle size, nest density, and visitor abundance, were measured in the four types of orchards. [Results]  PC, DA and NNS had significantly higher soil penetration resistance, bulk density and temperature, but significantly lower water content, than NS. No significant differences in soil particle size between the four types of orchards were detected. PC, DA and NNS had significantly lower nest densities and visitor abundance than NS orchards. Nest density was significantly, and positively, correlated with soil traits and soil penetration resistance could be used as an indicator to determine whether soils were suitable nesting sites for digger bees. We systematically measured the soil penetration resistance of all PC and DA orchards in the Karst region and found that these soils were compacted, with values higher than the threshold (2.50 MPa) below which digger bees prefer to build their nests. [Conclusion]  The soils in the Karst region in Wenshan, Yunnan are not suitable nesting sites for digger bees, which may have resulted in their decline in this region.