In order to solve the problems of poor drillability and slow ROP, reduce the friction drag in slide drilling of the horizontal section, and improve drilling efficiency in drilling horizontal wells in hard formation for oil and gas, a fluid powered efflux hammer was developed for horizontal drilling through the analysis of the tool working principle and the improvement of the structure and parameters. On the basis of bench tests, the performance parameters , drilling tool assembly and rotary percussive drilling parameters were further optimized, and the field tests for horizontal drilling were carried out. The results of field tests showed that the fluid powered efflux hammer has a remarkable effect in increasing the ROP over the horizontal well section, so it is worth further research. However , the failure of the tool in the horizontal section affects its effect in improving the ROP. In this paper, the problems of the tool are analyzed theoretically and experimentally, with the improvement plan put forward.