Abstract: Effects of Piriformospora indica treatment on seed germination and seedling growth of Dongbi longan (Dimocarpus longan) were investigated. After a treatment with P. indica, the germination rate of the longan seeds stored at room temperature for three days increased significantly at P < 0.01. Two months after sowing, the root count and height of the seedlings significantly increased as well (P < 0.01), and the weights of branched roots, main roots, above-ground and entire plantlet all significantly increased (P < 0.05). The average length of main roots on the treated seedlings was shorter than that on control, but not significantly different. Nor was there any significant difference on leaf count. It appeared that by treating the seeds with P. indica the germination rate and seedling growth of Dongbi longan could be improved.