The objective of this study was to improve the quality of pineapple plant silage by leucaena supplementation and using it as roughage during the shortage of green forages. There were 5 treatments as follows :- 1. Pineapple plant 100%, 2. pineapple plants mixed with leucaena 5%, 3. pineapple plants mixed with leucaena 10%, 4. Pineapple plants mixed with leucaena 15% and 5. grass 100%. The Completely Randomized Design (CRD) with four replications each was used in this experiment. All treatments were put in 1%NaCL2 and tightly sealed in plastic containers. They were stored at room temperature for 21 days. The silage treatments were evaluated on physical characteristics, chemical composition and fibre analysis. The physical characteristic showed that the color of treatment 1 was a yellow green color, a good characteristic of silage. For treatments 2, 3 and 4 there was a light brown color. Treatment 5 was a dark brown in color. The aromas of all silage treatments were aromatic and acidic like pickled fruit. The evaluation of chemical composition showed a highly significant difference among the treatment groups (p < 0.01). Treatment 4 was the highest in protein and metabolizable energy percentage with the averages of 8.19% and 3,697.17 kcal/k, respectively. The percentage of crude fibre was reduced with the increase of leucaena in the silage. Treatment 5 was the highest in crude fibre. The pineapple plant silage mixed with leucaena could improve the quality of silage for ruminants.