In this study, the selfincompatible line variety ‘Aijiaohuang’ of Brassica campestris L. ssp. chinensis Makino was used as the experimental material. The BcMLPK gene was constructed into the pTY vector by VIGS technique and quantitatively analyzed, to research the function of BcMLPK gene in selfincompatibility. The results showed that: (1) the BcMLPK gene sequence has a length of 1 443 bp and encodes 480 amino acids. Comparison of the amino acid sequence of BcMLPK protein with MLPK amino acids of other species indicates that the BcMLPK gene has a highly conserved domain with other genes. (2) Construction of pTYBcMLPK vector, using the gene gun method to infect ‘Aijiaohuang’, the new true leaves have obvious symptoms such as mosaic, select the diseased leaves and flower buds for realtime quantitative qRTPCR identification. The expression level of BcMLPK gene in the infected plants was about 50% of the control group. (3) The plants were selfpollinated at the flowering stage, and the experimental group had obvious podforming phenomenon, while the control group showed the pistil failed to elongate significantly, indicating abnormal fertilization. The statistical results showed that the selfincompatibility index and seed setting rate of the experimental group were higher than those of the control group. Studies have shown that the silencing of MLPK gene is able to inhibit the expression of BcMLPK transcriptional level of the selfincompatible gene of ‘Aijiaohuang’.