Abstract: To explore the regulation of nitric oxide(NO) induced by marching in dry hot desert,the nitric oxide(NO) in plasma was detected.The results showed that both at 3 5km/h.and 5 0km/h.with 0 or 15kg,the concentrations of nitric oxide in plasma in marching groups were much less than that in control(P<0.01),the level of nitric oxide in the plasma in the group marching for 3 hours at 5.0km/h.was obviously higher than that at 3 5km/h.(P<0.01).Without load,only the concentration of NO in the group marching for 3 hours.is evidently less than that for 1h.at 3.5km/h.With 15kg,the contration of NO in the group marching for 3h.Is obviously less than those for 1 and 2 hours.at 3 5km/h.