Provided are an optical alignment device applied to an assembly process of an optical transmitter and an optical receiver that include multi-channel optical elements and optical waveguide elements for optical communication, and an optical alignment method thereof. The optical alignment device includes an element fixing case with a mounting space formed thereinside and an element insertion hole communicating with the mounting space formed at an upper side thereof, and a light source mounted in the mounting space of the element fixing case and configured to emit light toward a lower side of an optical element or an optical waveguide element which is inserted into the element insertion hole to check a position of a core.