The aim of the present study is to shed light on the evaluation of biochemical parameters of liver function in case of affection by fatty liver induced by primary ketosis, graduation of this disease depending on biochemical parameters into three degrees (severe, moderate and mild) treatment of some cows in different degrees of the disease was carried out depending on the changes of the histological liver investigation and detection of fat deposition in hepatic cells. The measured biochemical parameters were (glucose, urea, total protein, albumin, globulin, bilirubin, AST, GGT and CPK). The result revealed a significant increase in estimated enzymes (AST, GGT and CK) there were also in both severe and moderate groups when compared with the control cows, Also a significant decrease in albumin concentration in case of severe and moderate groups when compared with the control cows in addition result revealed a significant increase of BHBA in blood serum of diseased cows compared with control cows. In conclusion it was obvious that liver function tests (AST, GGT, CK, albumin and BHBA) have an important role in diagnosis of fatty liver in case of dairy cows as they showed a clear difference between affection levels and healthy cows (control).