The process of designing and computing the pulse field of kicker magnet with ferrite cores for new injection system of HLS storage ring is presented. Firstly, the requirement of field quality is derived from tracking study of injection course. Then, the generation of pulse field is qualitatively analyzed and numerically calculated and the effects of eddy currents in core on magnetic field homogeneity are discussed under different conditions. According to the results of the calculation and the requirement fo...