Silage is an important way to ensure long-term storage and sustainable supply of straw, and more convenient for storage and transportation after compression. However, when silage compressed straw was used for anaerobic digestion to produce biogas, there is a lack of influence on the biogas yield performance of compressed silage parameters. Corn stovers were used as substrate to study the changes of characteristics after different time and different ratios of compressed silage, and the anaerobic digestion biogas yield characteristics were tested. The results showed that with the extension of silage time, the material loss of corn stover was serious, the high-density of corn stover in the longterm silage can effectively reduce the dry matter loss. After 300d of silage, the cellulose mass fraction of corn stalks was decreased significantly. But after compression, the mass fraction of cellulose and hemicellulose was higher than that of the original straw by 8.5% and 10.6% under the 1∶6 compression ratio, respectively. The TS recovery rate of the uncompressed group was 26.5% at 300d silage, and the TS recovery rate of the 1∶6 compression group was 51.0%. It was 92.5% higher than that of the uncompressed group. The prolongation of silage time significantly reduced the biogas potential of corn stover. At 40d of silage, the cumulative biogas yield of the uncompressed group was 23.2mL/g, the 1∶6 compression group was 282.9mL/g. At 300d of silage, the biogas yield potential of the uncompressed group was lost (2.3mL/g), and the cumulative biogas yield of the 1∶6 compression group was 200.3mL/g, indicating that high compression ratio was more beneficial to maintain the biogas performance of silage straw.