Abstract: Stylosanthes is a legume forage which has high protein content and good nutritional quality in tropical and subtropical areas. To promote the utilization of Stylosanthes, the effects of adding lactic acid bacteria and pineapple peel on the silage fermentation quality and aerobic stability were studied after 60 days storage. The experimental treatments were CK (no additive), LQ (commercial inoculant), LF (Lactobacillus fermentum), LP (L. plantarum), LS (L. rhamnosus), B (20% pineapple peel), BLQ (B+LQ), BLF (B+LF), BLP (B+LP), and BLS (B+LS). Stylosanthes silage had few water soluble carbohydrates and lactic acid bacteria, together with poor quality and a high pH (>5.0) when there were no additives. All the additives significantly reduced pH, increased lactic acid contents (P＜0.05), and considerably improved the silage fermentation quality compared with the control. The contents of butyric acid and NH₃-N in the silage with addition of pineapple peel only were significantly higher than those with only lactic acid bacteria added (P＜0.05). The pH was not significantly different from LQ, LF, and LS (P＞0.05). There were no significant differences between the four lactic acid bacterial treatments in any of the indices (P＞0.05) except that LP had a higher acetic acid content and lower butyric acid content than the others. Combining pineapple peel and any lactic acid bacteria improved the silage fermentation quality of Stylosanthes, especially for BLP, which had a lower pH, lower acetic acid and NH₃-N contents, higher lactic acid bacteria content and, higher ratio of lactic acid to acetic acid. All the silages including the control had good aerobic stability.