Objective To investigate the changes of thyroid hormone in peritoneal dialysis patients and analyse its impact factors, as well as the therapeutic effects of small dose of thyroxine.Methods 150 uremic patients in Hunan Provincial People’s Hospital from December 2013 to December 2014 were selected, 70 cases of uremia non-dialysis patients were divided into group A, while 80 uremia peritoneal dialysis for more than half a year were divided into group B.70 cases healthy examinees during the same period in our hospital were selected as control group ( group C ) . The total triiodothyronine (T3), total thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), thyroid stimulating hormone (TSH), hemoglobin (Hb), serum albumin (ALB), total cholesterol (TC), triglyceride (TG), serum creatinine (SCr), C reactive protein (CRP) and left ventricular ejection fraction ( LVEF) , subjective global assessment of nutritional act ( SGA) and other indicators were detected in three groups.Patients in group B were divided into two sub-groups according to thyroid hormone levels: B1 group had normal thyroid level while B2 abnormal.And the administration of small dose of thyroid hormone was given to patients in group B2, and the effect of the administration was evaluated by the above indexes.Results The FT3 in group A and B were significantly lower than that in group C (P<0.01).There were significant differences of levels of ALB, CRP, SGA between group B1 and group B2, and the FT3 level in group B was significant correlated with SGA, ALB, LVEF(r=0.815,P<0.001;r=0.780,P<0.001;r=0.953,P<0.001).After treated with small dose of thyroid hormone, FT3 and LVEF were improved while FT4, TSH, ALB, SGA, CRP were not improved in group B2.Conclusion The thyroid hormone level in patients with continuous ambulatory peritoneal dialysis decreases which is dominated with FT3.The decreased thyroid level is significantly correlated with nutrition ( ALB, SGA) and left ventricular function.The administration of small dose of thyroid hormone can improve the left ventricular systolic function.