Abstract: Significant progress has been recently reported on beam combination of fiber laser arrays using coherent combining and spectrum combining technology.Analyzing the basic requirement for the fiber laser,key technology,number scalability,beam quality,system stability and beam steering comes to a comparative study on these two technologies.The results show coherent combining using master oscillator power-amplifierfiber arrays configuration and spectrum combining cannot give high power laser beam with good beam quality at the same time that we have to balance the pros and cons of each technology for different application.