This research was carried out from May to August 2011 at the Haibei Alpine Meadow Ecosystem Research Station, Chinese Academy of Science, Qinghai Province. Wild plateau pikas (Ochotona curzoniae) were captured from May to August in order to observe monthly changes in total cholesterol, triglyceride, phospholipid, and high-density lipoprotein cholesterol levels in serum. The serum lipid levels were also examined after the pikas were given various doses of tannic acid for different periods by intragastric administration in July. The results showed that the serum lipids responded differently to tannic acid. The total cholesterol level did not change significantly after administration of tannic acid. The serum triglyceride level decreased sharply after administration of middle and high doses of tannic acid for one day and four days; similarly, the levels of serum phospholipid were lower in both the middle-dose and high-dose groups compared with those in the control group. However, the level of serum high-density lipoprotein cholesterol in the high-dose group was higher than that in the control group after tannic acid administration for one day and four days. In the wild plateau pikas, the serum triglyceride and phospholipid levels increased from May to July, but decreased in August. In contrast, the levels of serum total cholesterol and high-density lipoprotein cholesterol decreased from May to July, but increased in August. A negative correlation was observed between triglyceride and high-density lipoprotein cholesterol. Our results indicate that intragastric administration of some dosages of tannic acid can reduce the triglyceride and phospholipid levels and increase the high-density lipoprotein cholesterol level in the serum of plateau pikas in a short period. The variation in serum lipids observed among the different months may have been related to the nutritional and reproductive conditions of the wild plateau pikas.