Abstract: Objective：To explore the effect of single left ventricular pacing achieved cardiac resynchronization therapy (CRT) and the change of right ventricular systolic function by using three chamber pacemaker rate adaptive atrio-ventricular delay function. Methods：Thirty patients with heart failure were selected, and were randomly divided into single left ventricular pacing group and double ventricular pacing group (15 patients in each group). The differences of AVD, QRS duration, LVEF, LAD, LVEDD, MRA, TAPSE, LVFT/RR, IVMD, and SPWMD were compared between the two groups before surgery and 12 months after surgery. The effect of the single-left ventricular pacing and the traditional biventricular pacing, and the changes of the systolic function were evaluated after the cardiac resynchronization treatment. Results：Compared to the preoperative period, LVEF, TAPSE, and LVFT/RR were increased, and AVD, QRS duration, LVEDD, MRA, IVMD, and SPWMD were reduced 12 months after the operation both in the single left ventricular pacing group and the double-ventricular pacing group, and the difference was statistically significant (P<0.01). Compared to single-left ventricular pacing group, AVD, TAPSE, and LVFT/RR increased (P<0.01); QRS and program-controlled optimization time shortened (P<0.01), and pacemaker battery life expectancy and the MRA decreased (P<0.05) in the double ventricular pacing group after the operation. Conclusions：Single-left ventricular pacing via rate adaptive atrio-ventricular delay and biventricular pacing can improve cardiac function in patients with heart failure. The former is superior to the latter in extending the left ventricular diastolic filling time, shortening the QRS interval and improving the right ventricular systolic function, and can shorten the program control optimization time and prolong the battery life of the pacemaker.