Abstract: This experiment was conducted to assess the use of peanut vine to increase nitrogen availability in the diet of dairy cows. Twelve healthy Chinese Holstein dairy cows in mid-lactation were allotted to 3 groups with 4 replicates based on production performance, lactation stage, body weight and physiological status and feed different rations. The trial used a 3×3 Latin square design including three periods; each period had a 15 day pre-trial period and a 6 day sampling period. Cows were fed diets with peanut vine to corn silage ratio of 1.0∶3.9 (A), 1.0∶1.2 (B) and 1.0∶0.4 (C). Dry matter intake, milk production and blood traits were not affected by the peanut vine∶corn silage ratio (P>0.05). There were also no differences in milk composition (P>0.05), but milk somatic cell count showed a decrease trend with an increase in peanut vine content; somatic cell count of group B decreased by 35.4% compared with group A. The economic performance was increased by increasing peanut vine in the diet. Feces nitrogen (N)/N intake was decreased in group B (P<0.05). The effects of peanut vine∶corn silage ratio on production, nitrogen use and economic benefit of dairy cows was considered; N use and economic benefits were greatest when the peanut vine∶corn silage ratio was 1.0∶1.2.