NAC transcription factor is a new-found and multifunctional transcription factor in plants. The purpose of the paper is to study the relative expression trends of BnNAC transcription factor gene under cold (4°C), salinity (200 mM NaCl) and abscisic acid (ABA) (100 μM) stress in Brassica napus. The functional region of BnNAC gene was cloned through the homologous cloning method. The sequences of nucleic acid and amino acid were analyzed using BLAST and DNAMAN software. Relative expression trends of BnNAC gene were detected by applying real-time relative quantification PCR (RT-qPCR) under cold, salinity and ABA treatment. A 440 bp BnNAC gene segment was acquired in Brassica napus. BnNAC gene expressions of Brassica napus seedlings were induced under cold, salinity and ABA treatment conditions. The results of RT-qPCR analysis revealed that, under salinity, cold and ABA conditions, the relative expression of BnNAC gene increases with time, reaches the peak at 24h, 3h, 12h respectively and then decreases. Our research showed that BnNAC plays a positive role in salinity, cold and ABA stress response.