[Objectives]The species and distribution of root-knot nematodes in tobacco growing regions of Yunnan were investigated,in order to provide reference for comprehensive prevention of root-knot nematodes disease and tobacco variety layout. [Methods]Fifty-four samples of root-knot nematode host on tobacco crops were collected from Kunming,Qujing and Yuxi cities in Yunnan from August to October in 2015. The species of root-knot nematodes were identified by observing perineal patterns and molecular biological testing( PCR of ribosomal DNA of ITS region and sequence characterized amplified region,SCAR). [Results] There were 24 samples belonging to Meloidogyne arenaria,accounting for 44. 44%; seven M. incognita samples,accounting for 12. 96%; one M. javanica sample,accounting for 1. 85%. Eleven samples were compound populations of M. javanica and M. arenaria,accounting for 20. 37%. Five were compound populations of M. incognita and M. arenaria,accounting for 9. 26%. Three were compound populations of M. incognita and M. javanica,accounting for 5. 56%. Three belonged to compound population of M. incognita,M. javanica and M. arenaria,accounting for 5. 56%. [Conclusions] The species of root-knot nematodes in tobacco growing areas of Yunnan mainly include M. incognita,M. javanica and M. arenaria. M. arenaria is the dominant population. [Objectives] The species and distribution of root-knot nematodes in tobacco growing regions of Yunnan were investigated, in order to provide reference for universal prevention of root-knot nematodes disease and tobacco variety layout. [Methods] Fifty-four samples of root- knot nematode host on tobacco crops were collected from Kunming, Qujing and Yuxi cities in Yunnan from August to October in 2015. The species of root-knot nematodes were identified by observing perineal patterns and molecular biological testing (PCR of ribosomal DNA of ITS region and sequence characterized amplified region, SCAR). [Results] There were 24 samples belonging to Meloidogyne arenaria, accounting for 44. 44%; seven M. incognita samples, accounting for 12. 96%; one M. javanica sample, accounting for 1. 85%. Eleven samples were compound populations of M. javanica and M. arenaria, accounting for 20. 37%. Five were compound populations of M. incognita and M. arenaria, accounting for 9.26%. Three were compound populat ions of M. incognita and M. javanica, accounting for 5. 56%. Three belonged to compound population of M. incognita, M. javanica and M. arenaria, accounting for 5. 56%. [Conclusions] The species of root- knot nematodes in tobacco growing areas of Yunnan mainly include M. incognita, M. javanica and M. arenaria. M. arenaria is the dominant population.