In order to develop and utilize spinach leaf protein resources effectively, the spinach leaves were used as raw material in this work. Based on the single factor experiments, Box-Behnken design was adopted to investigate the influence of four factors: the dilution ratio, gas velocity, temperature and pH on recovery rate and enrichment ratio of leaf protein from spinach leaves. The optimum conditions for the foam separation of spinach leaf protein were found: diluting time of 16 times, gas velocity of 260 mL/min, temperature of 40 ℃, pH value of 7.5. Under these conditions, the recovery and enrichment ratio reached to 81.56% and 14.94, respectively. The results show that foam separation technique is an effective method to separate leaf protein from spinach.