Abstract: To investigate the effects of enzyme preparation on performance of layers,270-day-old Hy-line brown layers were assigned randomly into two groups.Supplementation of enzyme preparation at a level of 0.4% increased laying rate by 7.51%（P〈0.05）,made age at the first laying be 8.5-9 d earlier than expected,reduced feed-egg ration by 7.60%（P〈0.05）,increased average egg weight by 5.13%（P0.05）,largely decreased feed cost and reduced or stopped the occurrence of diarrhea.