Pak-choi is one of the most important vegetable crops in China. Turnip mosaic virus (TuMV) is one of its main pathogen. Screening the molecular marker linked to the TuMV resistance gene is an efficient method to improve pak-choi breeding. In this paper, a dominant gene, TuRBCH01, has been mapped. 180 F2 individuals were inoculated with TuMV-C5 and tested by direct ELISA. The 3:1 ratio of F2 hybrids segregation proved a single dominant allele for TuMV resistance. Amplified fragment length
polymorphism (AFLP) technique and bulked segregant analysis (BSA) method were used to study the F2 population. An AFLP marker (EccMctt3) linked to TuMV resistance gene with 7.8cM map distance was identified.