Effects of the addition amount of different thickeners (maltodextrin, xanthan gum, sodium carboxymethyl cellulose) on the quality of freeze-dried Pleurotus eryngii powder were studied by investigating the indexes of bulk density, hygroscopicity and instant solubility. In order to obtain a better product quality, the best combination of thickeners was optimized by single factor, orthogonal experiment and comprehensive analysis method. The results showed that adding three thickeners alone can improve the quality of freeze-dried Pleurotus eryngii powder. The effect of maltodextrin was the most significant, followed by xanthan gum and sodium carboxymethyl cellulose. The best combination was maltodextrin 15%, xanthan gum 0.15% and sodium carboxymethyl cellulose 0.8%.