Objective To observe the volume changes incurred by sacubitril/valsartan and its effects on cardiac structure and functions in patients with chronic heart failure (CHF) complicated with renal insufficiency. Methods A total of 84 CHF patients complicated with renal insufficiency were consecutively enrolled, who were admitted to the First Hospital of Qinghuangdao from December 2020 to March 2022. They were divided into sacubitril/valsartan group (n=48) and control group (n=36). The sacubitril/valsartan group received sacubitril/valsartan and the control group valsartan alone. On the follow-up visit after 6 months of medication, 24-hour urine volume, diuretic dose, and brain natriuretic peptide (BNP) level were measured, New York Heart Association (NYHA) classification was performed, and cardiac structure and functions were evaluated by echocardiography in the two groups. Results Compared with the control group, 24-hour urine volume in sacubitril/valsartan group increased significantly [(1514.38±694.73) vs (1003.33±178.92) ml; P<0.01], and NYHA classification was significantly improved (P=0.032) after therapy. Compared with the baseline, the dose of diuretic [(19.38±7.55) vs (23.75±7.89) mg] and the level of BNP [811 (250,1481) vs 1 980 (727,5014) pg/ml] decreased significantly (P<0.01), and the urine volume in 24 h [(1514.38±694.73) vs (890.63±121.45) ml] increased significantly (P<0.01) at 6 months in the sacubitril/valsartan group. Compared with the control group, stroke output (SV) [(102.39±20.85) vs (77.98±18.51) ml], cardiac output (CO) [(7.39±2.18) vs (5.84±1.72) L/min], left ventricular ejection fraction (LVEF) [(36.87±6.16)% vs (33.08±7.59)%], mitral diastolic blood flow velocity E peak and A peak ratio (E/A) [1.30 (1.25,1.82) vs 1.04(0.59,2.53)] increased significantly ( P<0.05 for all), and left atrium (LA) [(42.97±6.01) vs (48.17±5.17) mm]decreased (P<0.05) in the sacubitril/valsartan group after therapy. The left ventricular end-diastolic diameter (LVEDD) [(64.9±10.3) vs (69.0±12.1) mm], left ventricular end-systolic diameter (LVESD) [50.5 (50.0,56.1) vs 54.0 (48.3,61.9) mm] and LA [(42.97±6.01) vs (47.61±8.06) mm] in the sacubitril/valsartan group decreased significantly and SV [(102.39±20.85) vs (68.13±29.96) ml], CO [(7.39±2.18) vs (5.66±2.49) L/min], E/A [1.30 (1.25,1.82) vs 0.93 (0.88,1.10)] and LVEF [(36.87±6.16)% vs (27.26±6.24)%] increased significantly at 6 months compared with the baseline (P<0.01 for all). Conclusion Compared with valsartan alone, sacubitril/valsartan can significantly relieve the volume overload in the CHF patients complicated with renal insufficiency, optimize the volume management measures, and enhance cardiac systolic and diastolic function.