Objective To investigate the efficacy of different dosage of tolvaptan in treatment of hyponatremia with chronic heart failure (CHF) for the elderly patients. Methods A total of 72 CHF elderly patients complicated with hyponatremia hospitalized in Yangzhou Friendship Hospital from October 2014 to February 2017 were recruited in this study. They were randomly divided into control group, low-dosage group and normal-dosage group (n=24 for each group). The patients of the control group was given conventional treatments including anti-heart failure therapy and slow venous infusion of 3% sodium chloride (250 ml/d). In addition to conventional treatment (without diuretic), the patients of the 2 treatment groups were given tolvaptan 7.5 and 15.0 mg/d respectively. In 7 d after the treatment, the clinical efficacy, serum sodium level, N-terminal B-type brain natriuretic peptide precursor (NT-proBNP), quality of life and length of hospital stay were compared among 3 groups. SPSS statistics 17.0 was used to analyze the data. The measurement data were expressed as mean±standard deviation ([AKx-D]±s), and Student’s t test was employed for the comparison between groups. Enumeration data were expressed as percentage, and inter-group comparison was carried out with Chi-square test. Results Compared to the indices before the treatment, the score of Minnesota Living With Heart Failure Questionnaire (MLHFQ), and serum levels of sodium and NT-proBNP were greatly improved after the treatment (P<0.05). Compared with the control group, the low- and normal-dosage treatment groups had significantly lower MLHFQ score and serum NT-proBNP level, and shorter length of hospital stay (P<0.05), and increased serum sodium level (P<0.05).Conclusion Both low (7.5 mg/d) and normal dosage (15.0 mg/d) of tolvaptan can significantly alleviate clinical syndromes of hyponatremia in elderly CHF patients.