Abstract: In order to explore the effect of microalgae on the growth performance in Qaidamford cattle, 24 healthy male Qaidamford cattle aged 2-3 years old weighing about 350 kg were divided into control and microalgae group, 12 heads in each group. The control group were fed with the basic diet, and the microalgae group were fed with the basic diet adding 200 g/head microalgae every day for 60 days. During the experiment, the changes of average daily feed intake were recorded and the total average daily feed intake was calculated; the changes of body weight, body size and serum triiodothyronine（T3）, thyroxine（T4） and growth hormone（GH） levels were detected before and after feeding. The animals were slaughtered after experiment, and the organs and tissues were separated to calculate the dressing percentage. The results showed that, with the increasing of feeding days, the average daily feed intake in both two groups showed an upward trend, while the upward trend of microalgae group was more obvious than that of the control group. Compared with control group, total average daily feed intake of microalgae group had no significant difference（P＞0.05）; the body weight, body height and the dressing percentage significantly increased（P＜0.05）; circumference of cannot bone increased extremely significantly（P＜0.01）; and the expression levels of growth related hormones T3, T4 and GH were significantly increased in microalgae group（P＜0.01）. It indicated that microalgae could increased the growth related hormones levels, accelerated the growth and development of Qaidamford cattle, and promote the related growth performance in Qaidamford cattle.