Objective We investigated the effect of sodium nitroprusside on microvascular blood flow of vital organs in a rat model after cardiopulmonary resuscitation (CPR), in order to find new ways for improving microcirculation perfusion after cardiopulmonary resuscitation (CPR) in rats. Methods SD rats as experimental subjects after anesthetizing, fixing, endotracheal intubating and catheterizating of femoral artery and femoral vein, the rats were randomly divided into the sham group (n=8), control group (n=8) and experimental group (n=8). Sham group: thoracotomy at the beginning of the experiment and injected colored microspheres into the left ventricle at the time of 0 min, 15 min and 40 min. Control group and the experimental group were stimulated epicardially by electrical to establish cardiac arrest model, and cardiopulmonary resuscitation was carried out to achieve return of spontaneous circulation. The control group was infused normal saline 4 mL per hour and 5% glucose solution 2 mL per hour 15 min after the restoration of spontaneous circulation. Experimental group was infused normal saline 4 mL per hour and 5% glucose solution 2 mL per hour which soluted sodium nitroprusside 15 min after restoration of spontaneous circulation (SNP concentration of 0.01 mg/mL). Before the cause fibrillation, 15 min and 40 min after the restoration of spontaneous circulation, experimental group and control group were thoracotomyed and injected colored microspheres into the left ventricle. 5 min after the third microsphere was injected, rats were killed and heart brain, kidney, stomach, intestine, lung tissues were sampled, then the tissues were digested and microspheres were recovered to calculate the microcirculatory blood flow in vital organs. Results ①The number of the microspheres in per gram tissue at three time points of Sham group had no significant differences (P>0.05). ②In the control group and the experimental group, compared with the before fibrillation time, the microspheres in per gram tissue of heart, brain, kidney, stomach, intestine significantly decreased at the time of ROSC 15 min, and the microspheres in per gram tissue of lung significantly increased (P<0.05). ③In the control group, compared to the time of ROSC 15 min, the microspheres in per gram tissue of heart, brain, kidney, stomach, intestine had no significantly differences at the time of ROSC 40 min (P＞0.05). In the experimental group, compared to the time of ROSC 15 min, the microspheres in per gram tissue of heart, brain, kidney, stomach, intestine significantly increased at the time of ROSC 40 min (P＜0.05), and the microspheres in per gram tissue of lung significantly decreased (P<0.05). Conclusion ①After cardiac arrest, when rats reach restoration of spontaneous circulation, microcirculation blood flow of heart, brain, kidney, stomach, intestinal is decreased. ②Sodium nitroprusside can improve the microcirculation blood flow of vital organs in rats after cardiopulmonary resuscitation 40 minutes. 