Objective To investigate the effect of perfusion index of the injection flow rate of contrast medium on magnetic resonance image dynamic contrast-enhanced (DCE-MRI) of prostate cancer with different pathological grades. Methods Seventy patients with PCa、cardiac, normal renal function is and BMI≤25 kg/m2 were enrolled. The 2.5 mL/s, 5.0 mL/s dynamic enhanced injection velocity contrast agent was used for 35 patients and the reast 35 patients, respectively. All data was transferred to GE Advanced Workstation 4.3, and the indexes of the peripheral prostate cancerous zone were calculated by Functool2 of signal intensity time (SI-T), The time to minimum (Tmax), the whole enhancement degree (SImax%) and the maximum slope (Rmax) were calculated. The effect of different injection velocity on the dynamic enhanced perfusion index was analyzed. Results Tmax of pa-tients received 2.5 mL/s, 5.0 mL/s contrast agent injection velocity in the low risk group (Gleason score 2 to 6)、medium risk group (7 Gleason score) and high risk group (Gleason score 8 to 10) were (19.89 ± 2.76) s and (15.42 ± 1.68) s, (16.91 ± 2.34) s and (12.88 ± 1.73) s, (14.13 ± 1.81) s and (10.2 ± 1.42) s, with signifi-cant differences (t = 4.61, 3.1, 3.25, P < 0.01). The average SImax% of PCa in the two groups were (1.45 ± 0.17)%and (1.51 ± 0.27)%, (1.62 ± 0.12)%and (1.84 ± 0.18)%, (1.86 ± 0.16)% and (2.11 ± 0.28)%, Two groups of SImax% were statistically significant difference (t = -2.44, -4.55, -5.16, P < 0.05), respectively. The average Rmax of PCa of the two groups were (6.29 ± 2.62)% and (7.64 ± 4.09)%,(8.92 ± 4.21)% and (10.24 ± 9.09)%, (10.85 ± 2.89)% and (12.43 ± 3.51)%, with significant difference (t = -4.07,-3.85, -8.68, P <0.01). Tmax was shorter, SImax% and Rmax were higher of prostate cancer patients received 5.0 mL/s contrast agent injection velocity than those received 2.5 mL/s contrast agent injection velocity. Conclusion The dynamic enhancement perfusion index of prostate cancer patients received 5.0 mL/s contrast agent injection velocity is more sensitive than that of patients received 2.5 mL/s contrast agent injection velocity , which can improve the diagnosis of prostate cancer.