Blanching treatment is an important operation for most mushroom processing. Reutilizing the blanch water can avoid environmental pollution and reduce the waste of resources because some nutrients are dissolved into the water during blanching. The effect of blanching frequency on the contents of polysaccharide, soluble protein and soluble solids, conductivity and browning degree of blanch water of Pleurotus eryngii was investigated. The result showed that the contents of polysaccharide, soluble protein and soluble solids, the conductivity and browning degree of blanch water of P. eryngii increased gradually with the enhancement of blanching frequency. Furthermore, the increase rates of polysaccharide, soluble protein, soluble solids and conductivity were high from the first to the forth blanching and then the improvement became gently after the fifth blanching. This indicated the optimal blanching frequency was four times for recycling blanch water at the conditions of 1 cm thickness of mushroom slice and 1/2 ratio of mushroom to water. This study provides an useful basis for utilizing the blanch water of P. eryngii in a rational way.