The long-cycle life cathode material plays a key role in terms of energy and power density for lithium ion battery. In this work, a series of Sr-doped hierarchical porous nanofiber structure Li_1.2Mn_0.54Ni_0.13Co_0.13-xSr_xO₂ are synthesized via electrospinning combined with high temperature solid phase technology. As a result, Sr-doping can enhance the cyclic performance, suppress the voltage decay and stabilize the structure. With the incorporation of Sr, not only the crystal structure and morphology of Li_1.2Mn_0.54Ni_0.13Co_0.13-xSr_xO₂ are slightly changed, but also both the specific capacity and discharge voltage of the Li rich cathode are stabilized upon cycling. When x = 0.03, Li_1.2Mn_0.54Ni_0.13Co_0.1Sr_0.03O₂ delivers an initial discharge capacity of 213 mAh g^-1 and a capacity retention of 94.16 % at the 100th cycle. The influence of the percentage of dopeed Sr on the performance of the battery is analyzed. Rational Sr dopeing technology is an effective way to improve the electrochemical performance of Li rich manganese based material.