A sawtooth-free period is produced following the pellet injection in the pellet fuelled discharge of qα=3.4(where qα is the safety factor at the plasma boundary)in the HL-2A tokamak.Establishment of the current profile such as in the hybrid scenario is studied under the condition of pellet injection in HL-2A.It is shown that a q-profile of weak negative shear is produced immediately after the pellet injection,and it then evolves to a broad flat profile with q0>1(where q0 is the safety factor at the centre).The measured MHD mode structures evidence consistencies of the evaluated q-profile with locations of the q=1 surface in the sawtoothing period and of the q=2 surface in the sawtooth-free period.TRANSP analysis indicates that the energy confinement is enhanced substantially during and after pellet injection.which is resulted from the q-profile optimization and the plasma density peaking.