MYB transcription factors are involved in the formation of plant cell morphology and pattern, the regulation of secondary metabolism and the response to biological and abiotic stress, while the expression of tomato MYB (SlMYB86) under nitrogen deficiency stress has not been reported. In this study, the tomato SlMYB86 gene was amplified by RTPCR, cluster analysis and conserved domain sequence analysis were carried out, prokaryotic expression vector and induced purified protein were constructed, and the expression level of SlMYB86 under nitrogen deficiency and nitrogen resupply was detected by qRTPCR and Western blot, which laid a foundation for further exploring the function of tomato MYB86 transcription factor under nitrogen deficiency stress. The results show that: (1) tomato SlMYB86 and tomato SlMYB26 belong to the same branch in the evolutionary tree, with close genetic relationship, and SlMYB86 contained two Myb_DNAbinding conserved domains, belonging to R2R3MYB transcription factor. (2) qRTPCR analysis showed that SlMYB86 gene was expressed in tomato roots and leaves, and the expression of SlMYB86 was significantly higher than that of the control under nitrogen deficiency stress. (3) The prokaryotic expression vector pET28aSlMYB86 was constructed and transformed into E. coli BL21 (DE3). The results of SDSPAGE and Western blot showed that the best induction conditions of SlMYB86 protein were 0.5 mmol/L IPTG and 37 ℃ for 8 hours. The relative molecular weight of the target protein is about 41 kD, which is consistent with the expected size, and SlMYB86 prokaryotic protein with high purity is obtained. (4) Mice were immunized with the purified SlMYB86 protein to obtain the antibody. Western blot showed that the expression of SlMYB86 protein in tomato was upregulated after nitrogen deficiency stress, indicating that tomato SlMYB86 gene was involved in the response to nitrogen deficiency stress.