Fiber lasers have the advantages of high photoelectric conversion efficiency, transmitting laser with flexible medium, high power output, high beam quality, high compactedness and reliability. They are especially suitable as heat sources for two types of metal additive manufacturing technologies: powder bed fusion (PBF) and directed energy deposition (DED). This paper reviews the types, output power, and operating modes of fiber laser heat sources in those two additive manufacturing technologies, and the PBF and DED research status of fabricating typical metal materials. The relative density and mechanical properties of specimen manufactured by PBF and DED are higher than that of traditional casting and close to the level of forging. Finally, the research direction of fiber laser additive manufacturing technology is prospected, and the development trend of fiber laser is prospected according to the demand from those two kinds of metal additive manufacturing technology.