Productions of fermentative by-products, like glycerol, succinic acid, lactic acid and volatile acid, were used to evaluate the influence of the mixed fermentation with Pichia fermentans and Saccharomyces cerevisiae on wine quality. The mixed fermentations of the P. fermentans strain Z9Y-3 and the commercial S. cerevisiae F33 were performed in model grape juice with simultaneous and sequential inoculation protocols, two single-yeast pure fermentations were as controls. In the fermentative by-products analysis, the succinic acid and lactic acid were measured by liquid chromatography, the glycerol was measured by the method of sodium periodate oxidation, and the volatile acid was measured by steam distillation. Results showed that the participation of the P. fermentans isolate didn't change the fermentation course significantly, but the growth rate of P. fermentans is lower than that of S. cerevise during fermentation. Comparing with the pure S. cerevise fermentation, mixed fermentation enhanced the level of glycerol and decreased the volatile acid content. The sequential inoculation protocol had the highest number of active S. cerevise cells, the survive period of P. fermentans strain was the longest (7d), while the accumulation of glycerol was the highest (2.7g/L) and that of the volatile acid was the lowest (0.2g/L). During different fermentations, the levels of succinic acid and lactic acid rose firstly, and then declined, but the variation of their final amounts was little. It was concluded that the mixed fermentation of the P. fermentans isolate and S. cerevisiae had the application potential in winemaking based on the productions of the main fermentative by-products.