A method for manufacturing an artificial leather comprises the following steps. First, ultramicrofiber-forming fibers having an islands-in-sea type cross-sectional configuration are formed by blend spinning or conjugate spinning. Secondly, a porous reinforcement sheet of low compactness is formed from polyester, polyurethane or polyolefin by spunbonding, meltblowing or calendering. Next, the ultramicrofibers are entangled with the reinforcement sheet by needle punching or spunlace to form the complex reinforced ultramicrofiber nonwoven fabric. The nonwoven is impregnated or coated with an elastomer resin composition, and then subjected to a coagulating process, a washing process, a drying process and a removing process to produce a semi-product leather. Finally, the semi-product leather is then processed to produce the artificial leather.