Objective:To investigate the changes of natural killer (NK) cells, natural killer T (NKT) cells and T lymphocytes in the peripheral blood after nanosecond pulse ablation of hepatic vesicular hydatid in rats with different energy levels.Methods:A total of 32 SD rats were randomly divided into hepatic vesicular hydatid model group, low voltage group (1 000 V), medium voltage group (1 500 V) and high voltage group (2 000 V). The hydatid model of rats was established by selective injection of 100 μl of echinococcosis head suspension with concentration of 500/100 μl into the left hepatic portal vein in all the 4 groups. After 3 months, nanosecond pulse therapy was applied to the left lobe vesicular hydatid lesions in the low voltage group, medium voltage group and high voltage group. On the third day after treatment, flow detector was used to calculate the ratio of CD 4+ T to CD 8+ T in peripheral blood of four groups by CD 3+ T, CD 4+ T, CD 8+ T, NK cells and NKT cells. Results:CD 3+ T was expressed in the high voltage group with (62.08±2.75)%, the medium voltage group with (63.84±7.73)%, the low voltage group with (55.19±8.55)% and the control group with (54.76±8.28)% ( P<0.05). CD 4+ T number was larger in high voltage group (43.7±6.51)% than medium voltage group (38.82±5.47)%, low voltage group (37.31±6.96)% and model group (38.12±3.04)% ( P<0.05). CD 8+ T ratio in the high voltage group was (20.03±2.40)%, the medium voltage group was (21.22±1.74)%, the low voltage group was (19.00±3.06)%, and the model group (20.56±3.98)%, with no statistically significant difference ( P>0.05). NK cells ratio in high voltage group was (6.49±1.60)%, medium voltage group was (3.02±0.32)%, low voltage group was (3.42±0.91)% and model group was (3.44±0.55)% ( P<0.05). NKT cells ratio in high voltage group was (1.53±0.16)%, medium voltage group was (0.82±0.09)%, in low voltage group was (0.70±0.17)% and model group (0.78±0.10)% ( P<0.05). CD 4+ T/CD 8+ T high voltage group was (2.26±0.65), medium voltage group was (1.90±0.40), low voltage group was (1.98±0.37) and model group was (2.06±0.35) ( P<0.05). Conclusion:High voltage (2 000 V) increased number of T, NK and NKT cells in peripheral blood compared with medium voltage (1 500 V) and low voltage (1 000 V), which may be the immune response of the body caused by nanosecond pulse ablation of hepatic vesicular hydatid in rats.