Abstract: Adopting smooth round-section specimens, through axial loading low cycle fatigue test controlled by strain mode, effect of loading frequency and strain ratio on low cycle fatigue life of 10CrNi5Mo high strength steel were investigated. The results indicated that no significant influence of loading frequency on fatigue life was observed for the frequency in the range of 0.05-0.1 Hz, however, with loading frequency increasing to 0.8 Hz, fatigue life increased and then fatigue life dropped for increasing loading frequency to 1.0 Hz. When the maximum strain being constant, with strain ratio increasing (from -1 to -0.3), fatigue life of the steel increased gradually and when stain ratio arrived at -0.3, the fatigue life improved markedly with strain ratio further increasing, which would provide reference for engineering application of 10CrNi5Mo high strength steel.