Abstract: Objective To investigate the effect of low calcium dialysate on cadiac function in CAPD patients. Methods Thirty-one CAPD patients were selected in this study.Standard calcium dialysate solution was changed to lower calcium dialysate solution.The cardiac function were echocardiographically examined at the beginning and the end of this study,respectively.The serum biochemical indicators and standed 12-lead electrocardiogram were examined at the beginning and the end of this study,respectively. 15 age- and sex-matched controls were also observed. Rusults After changing to PD4,secrum calcium concentration decreased, and PTH increased significantly.The changes in QTd、QTcd were not statistically significant.The changes in E/Amax、IRT were statistically significant.The change in serum calcium has negtive relation with the change in E/Amax and positive relation with the change in IRT. Conclusion There were favorable changes in left ventricular diastolic function after treatment with low calcium dialysate.The changes may be associated with the ameliorate of calcium phosphate metabolism and calcium overload.