This experiment was conducted to investigate the effects of composite enzyme preparation FE907 on milk production and disease resistance of lactating dairy cows. A total of 28 lactating Holstein dairy cows were randomly allocated into two groups with 14 ones per group, which were fed a total mixed ration (TMR) alone and supplemented with 20 g/d·cow of FE907, respectively. The feeding experiment lasted four weeks. The results showed that the daily milk production was increased by 1.6 kg/d (P > 0.05) in response to dietary supplementation of FE907. In addition, an increase of 0.08% in the fat content of milk and of 0.09 kg/d in the production of milk was observed over the control group with significant differences (P < 0.05). The protein content of milk and the production of milk protein were also increased by 0.06% and 0.07 kg/d, respectively. The benefit per day from one cow was 6.28 RMB more than the control group. It is concluded that supplementing 20 g/d·cow of the enzyme preparation to the diet has a positive effect on improving the milk yield, milk composition and economic benefit while reducing the risk of developing mastitis.