Provided is a method of fabricating an optoelectronic integrated circuit chip. In particular, a method of fabricating an optoelectronic integrated circuit chip is provided, in which an optical absorption layer of a wave-guide type optical detector is grown to be thicker than a collector layer of a hetero-junction bipolar transistor by using a selective area growth by metal organic chemical vapor deposition (MOCVD) method, and the wave-guide type optical detector and the hetero-junction bipolar transistor are integrated as a single chip on a semi-insulated InP substrate, thereby readily realizing the wave-guide type optical detector improved in quantum efficiency and having the ultra-high speed characteristics.