Abstract: In order to explore the effects of co-fermentation of Leuconostoc mesenteroides L5 and Kazachstania exigua M1 on the physicochemical properties of low-salt and low-acid fermented mustard during fermentation process and storage period, the co-fermentation group was compared with a natural fermentation group and a fermentation group solely with the lactic acid bacterium L5. The pH, total acid, total ester and nitrite content etc. during the fermentation process and storage period were measured. The texture and color difference of fermented mature paocai and accelerated preserved paocai were analyzed alongside sensory evaluation. The results showed that L5 and M1 co-fermented paocai contained nitrite as lowest as 1.45 mg/kg , and total acid (2.46 g/kg) was significantly lower than that of the other two groups (P<0.05), respectively, total ester (3.79 g/kg) and score in sensory test were significantly higher than that of the other two groups (P<0.05). After the paocai product kept at 37 ℃ for 75 days for accelerated storage, the total acid content only increased to 3.10 g/kg, the total ester content increased to 4.16 g/kg, whereas the nitrite content further decreased to 0.91 mg/kg. Its low acid state and good sensory, texture and color qualities were maintained. It was proved that the addition of suitable yeast and lactic acid bacteria for joint fermentation could not only improve the flavor and quality of paocai, but also play a certain role in maintaining its preservability.