Recently, the coherent combining of high power fiber laser array has become a hotspot of research internationally, and the phase control electronics contributed greatly to the success of the coherent combining. A high-speed wavefront sensor is introduced to sample the wavefront and actively control the phase state of each individual optical fiber in a high average power fiber laser array,and accordingly the phase-locked output of the whole system is achieved.A single signal lightwave is taken as example in the paper,the research results are presented.We conclude from the research results that when closing the phase control feedback loop the phasefront can be locked to the quiescent state of phase.