Objective To study the clinical value of blood lipid test in the diagnosis of diabetes mellitus (DM). Methods From Jul. 2013 to Oct. 2014, a total of 50 patients with DM in our hospital were selected as the clinical research objects (study group). At the same period, another 50 healthy people in our hospital were selected as control group. Both groups accepted blood lipid test, and their test results were compared. Results The indexes of TC, TG, LDL-C and ApoB in the study group were significantly higher than those in the control group, but the indexes of HDL-C and ApoA1 in the study group were lower than those in the control group, and the differences were statistically significant (P<0.05). The incidence rate of dyslipidemia in the study group was significantly higher than that in the control group, and the difference was statistically significant (P<0.05). Conclusion Blood lipid test which has great clinical application value, can be used as the basis for diagnosing diabetes in clinic. On the basis of blood lipid test, treatment plan could be made, treatment opportunity could be grasped, effective treatment could be given in time, and patients' life quality and life safety could be guaranteed.