Background Levosimendan can improve clinical symptoms and the cardiorenal rescue success rate, and stabilize hemodynamic parameters in individuals suffering from acute decompensated heart failure. In addition, Shenfu injection (SFI) has been shown to protect the ischemic heart and enhance myocardial contractility. Methods For this randomized control single-blind study, 101 patients with acute decompensated heart failure (ADHF) were enrolled and randomly assigned to control levosimendan (n = 51) and levosimendan + SFI injection (n = 50) groups. Attending physicians were not blinded for which arm the patients were allocated. Blood pressure, heart rate, the electrocardiogram, respiratory rate, fluid intake and urine output were all recorded 2 h and 24 h after drug infusions had commenced, and the cardiac index (CI) was monitored by ultrasonic cardiac output monitors. Results Median blood pressure was markedly increased in the levosimendan + SFI group after 2 h and 24 h from the initiation of infusions compared to levosimendan administration alone. Brain natriuretic peptide (BNP) concentrations were reduced after administrations of levosimendan + SFI or solely levosimendan (both P < 0.001). Alterations in BNP concentrations were not different in the combination and control groups. No differences were found between the 2 groups in heart rate or severe hypotension, but blood pressure (systolic blood pressure, diastolic blood pressure) and hemodynamic parameters including CI, cardiac output and stroke volume index responded better in the levosimendan + SFI group compared to the monotherapy levosimendan group. Conclusions Levosimendan + SFI was superior to treat ADHF patients compared to levosimendan monotherapy and produced significant improvements in hemodynamic parameters especially for ADHF patients with hypotension. Trail registration The study was prospectively registered at Chinese Clinical Trial Registry with registration number [ChiCTR2000039385] (10/25/2020).