Abstract: A new kind of microbial fermentation protein feed was developed in present study and its effect on the production performance of Holstein cows was evaluated. A total of 30 Holstein cows were randomly divided into experimental group and control group, and there were 15 cows for each group.The diet composition of the control group was concentrate supplement, silage and alfalfa hay adding 30% linseed cake, and that of the experimental group was concentrate supplement, silage and alfalfa hay adding 30% microbial fermentation protein feed. The experimental period was 60 d. The results showed that compared with the control group, the average daily milk yield for each cow of the experimental group was increased by 2.25%（P〉0.05）, the total increasing amount of average milk production for each cow of the experimental group during the experiment was 43.51%（P〈0.01）higher than that of the control group,the concentrate/milk yield ratio of the experimental group was reduced by 9.20%（P〈0.05）,the average gross profit for each cow of the experimental group was 40.34 Yuan higher and the economic benefit of the experimental group was increased by 3.53%.