Abstract: The causes of pica of monogastric animals and ruminants and its study survey were reviewed. The results showed that pica of livestock and poultry caused by nutrition deficiency were mainly the results of protein, minerals and vitamin deficiencies. Minerals deficiency were mainly the deficiencies of Se, Cu and Zn. Because rumen microorganisms could synthesize vitamin B for ruminants cattle and sheep,the vitamin deficiency of cattle and sheep were mainly of vitamin A and vitamin D.