The purpose of this experiment was to study the difference of conventional nutritional value, fermentation quality and rumen degradation rate of whole plant corn silage at different depths in silage silo under the most common silage filling, compaction, sealing and other management strategies for large-scale farms, and to provide theoretical support and practical guidance for rational production and utilization of whole plant corn silage. The silage samples were collected from large-scale farms (n=6) in Heilongjiang province. The conventional nutritional value, fermentation quality, starch degradation rate at 7 h, dry matter degradation rate (DMD), neutral detergent fiber degradation rate (NDFD) and crude protein degradation rate (CPD) at 24, 30 and 48 h of whole plant corn silage samples at different depths (upper, middle and under layers) were determined. For fermatation qualiy, the pH, contetns of starch, lactic acid, acetic acid, ammonia nitrogen and the amount of lactic acid bacteria, yeast and mold were determined, and then comprehensive evaluation was analyzed by membership function. The results showed as follows:1) the contents of dry mater, neutral detergent fiber and starch decreased with the increase of the depth of silage silo, but there was no significant difference in the contents of nutrients (P>0.05). Besides, there was no significant difference in contents of crude protein, crude ash and acid deter gent insoluble crude protein among three layers (P>0.05). 2) The results of comprehensive evaluation value of the whole corn silage in the middle layer was the highest, followed by the under layer, and the upper layer was the lowest. 3) For DMD of whole plant corn silage in different depths of silage silo, there was no significant difference among layers at 24 h (P>0.05), but after 30 h, DMD of whole plant corn silage in the middle layer was significantly higher than that in upper layer (P<0.05), but there was no significant difference between middle and under layers (P>0.05). For the NDFD, there was no significant difference among three layers at 24 and 30 h (P>0.05); however, after 48 h degradation in the rumen of cows, the NDFD in the middle and under layers was significantly higher than that in the upper layer (P<0.05), but the difference between the middle and under layers was not significant (P>0.05). At three time points, there was no significant difference in CPD and starch degradation rate of silage samples at different depths (P>0.05). It is concluded that there is significant differences in the quality of whole plant corn silage at different depths in the silage silo. With the increase of the depth of silage in silage silo, the loss rate of DM, starch and other nutrients increase, but the fermentation effects of pH and organic acids are better and rumen degradability increases. However, after reaching a certain depth, the fermentation quality tends to be stable, and the comprehensive evaluation results show that whole plant corn silage in the middle layer has the best quality. Therefore, in the process of silage production, we should pay attention to layer-by-layer compactionto, and the utilization of oxygen barrier membrane is recommend. In the feeding process, the material should be taken from top to bottom uniformly to reduce the impact of silage on consistency of diets.