Simulated indoor incubation experiment was carried out to explore the degradation dynamics of oxytetracycline (OTC) from different manures and the mechanisms were investigated as well. The results suggested that manures accelerated OTC entering soil and degrading period, and resembled the L-type curves. Both degradation rate and degradation percentage were significantly different for different antibiotics with different concentration (P < 0.05). At day 180, the OTC degradation percentage of chicken feces was higher than that of pig feces, and the highest degradation percentage reached to 85.4% and 92.3% respectively. The half-lives of chicken and pig manures were 26.98 d, 31.32 d respectively. Degradation percentage was negatively correlated with the amount of manures used and positively correlated with incubation time (v = A + Blnt, r > 0.96). At day 50, the photo-degradation and micro-degradation accounted for 20.03% and 3.16% of total reduction. 25.05% decreased in photo degradation and 2.50% increased in microbiological degradation. It is indicated that the degradation effects to OTC from pig manures was superior to chicken manures, photo decomposing played an important role in the process of degradation and indigenous soil microorganisms only had a little effect on it. With the extension of incubation time, microbiological decomposing became better, but photo decomposing became weaker.