This study aims to investigate using different ratios of urea-molasses in silage of food in vitro fermentation, feed value and quality production in feed. After being withered a little, the fodder plant was fragmented into 2-3 cm long pieces. 0, 2 and 4% molasses and 0, 0.5 and 1% urea were added. The treatment groups were UM1 (control), UM2, UM3, UM4, UM5, UM6, UM7, UM8 and UM9 supplemented with 0, 0, 0, 1, 1, 1, 1.5, 1.5, 1.5% urea and 0, 2, 4, 0, 2, 4, 0, 2, 4% molasses respectively, and a total of 54 silage samples, 9 × 6 parallel, were prepared, vacuumed in ready-made silage bags, and stored at 25 ± 2 °C for 60 days. After the silages were opened, pH, nutrient contents, Fleig scores (FS), in vitro digestibility parameters, energy contents, feed value and feed quality were determined, then the data were subjected to analysis of variance. The effects of urea and molasses additives added to the mixed forage plant silage on all parameters were found to be significant (P < 0.05, P < 0.01). The crude protein (CP) increased its application by UM7. Cell wall component (insoluble fibre in acid detergent (ADF) and neutral detergent insoluble fibre NDF) reduced its application by UM9. All these applications increased the FS. The addition of molasses increased the in vitro gas production, while the addition of urea decreased the production. True organic matter digestibility increased with the addition of molasses. As a result, it was concluded that UM9 application in silages would be appropriate for increasing feed value and feed quality, and the UM3 application in silage would be appropriate for improving true organic matter digestibility (TOMD).