The invention discloses a method for basic bath dyeing of nylon 56 fiber fabric. According to the method, the nylon 56 fiber fabric is dyed with vat dye or activated dye, wherein the nylon 56 fiber fabric is nylon 56 filament or nylon 56 short fiber fabric. Due to the difference in crystallization, the acid-base resistance of nylon 56 is quite different from that of ordinary nylon 6 and nylon 66. Under the same treatment condition, the fiber strength of nylon 56 is much lower, and thus nylon 6 and nylon 66 dyeing processes which are mostly studied are not completely applicable to dyeing of nylon 56. In the method, activated dye and nylon 56 are boned through covalent bonds, firmness is higher than that of ionic bonding in an acid bath, dyeing temperature is lower than that of a conventional dyeing method, and damage to fabric can be reduced by the adoption of low-temperature dyeing.