Abstract: Different diameter of pine bark, waste mushrooms media were selected for container seedling cultivation of 1-year Larix gmelinii in April2014 at Qianwei Forest Farm, Hebei province. Growth and root traits were determined in October 2014. The results showed that different substrateswith different diameter had significant effects on volume, surface area, length, diameter of root system, number of root tips and branched roots, andtheir traits were significantly correlated. The experiments demonstrated that the best substrate for seedling cultivation of L. gmelinii was pine barkwith diameter of 1≤d<2mm. Seedlings had the longest root system, the most root numbers and branched roots, the highest percentage of fine root.