Objective To observe the clinical efficacy and the effection on blood lipid level of subclinical hypothyroidism,clinical hypothyroidism treated with levothyroxin. Methods Collected 144 cases hypothyroidism patients,they were randomly divided into two groups according to the order of treatment, 72 cases in each group.Patients in two groups were both given hypoglycemic,pressure control, expansion of coronary artery and other conventional symptomatic treatment, patients in the observation group were given levothyroxine sodium. The hormone levels and blood lipid levels before and after treatment with the two groups were compared. Results After treatment, FT3, FT4 and TSH levels of the observation group were(6.77±0.72)pmol/L,(13.56±1.52)pmol/L and(3.25±1.20) m IU/L, significantly improved than before treatment and control group;while TC and TG levels were(4.15±0.88)mmol/L and(1.65±0.32)mmol/L, significantly reduced than before treatment and control group,and the difference between the two groups were statistically significant(P 0.05). Conclusion Levothyroxine treatment of subclinical hypothyroidism can significantly improve the efficacy of clinical hypothyroidism, thyroid function in patients, and reduce blood lipid levels, worthy clinical widely.