A pervasive positive abundance-range size relationship (ARR) has been challenged by recent studies which revealed negative and neutral trends in isolated systems (mountain ranges and islands). We expect that in a subtropical mountain range, small mammals should show a non-positive ARR due to geographical isolation and climatic stability (non-positive ARR hypothesis). Further, we expect a stronger non-positive ARR for species distributed at higher elevations (elevational distribution hypothesis) and with higher dispersal abilities (dispersal ability hypothesis). We examined the ARRs of small mammals in four mountains of southwest China and related species’ mean abundances to range sizes. To test the elevational distribution hypothesis, we examined the relationship between mean abundance and elevational range centre and compared the ARRs between the montane and alpine group. To test the dispersal ability hypothesis, we compared the mean abundance and range size between glires (more vagile) and insectivores, as well as their ARRs. We found a negative ARR in three mountains and a weak positive ARR in the other. A positive correlation between mean abundance and elevational range centre was found in each mountain, so was a higher mean abundance of glires. Glires showed a stronger non-positive ARR than insectivores across mountains. The observed non-positive ARR is primarily driven by the prosperity of endemic species and poverty of widespread species given their different levels of specialization to subtropical montane habitats. Higher dispersal ability may cause a stronger non-positive ARR of small mammals in a mountain range where local dispersal is easier than regional dispersal.