Abstract: The fabrication process,investigation of femtosecond laser direct writing optical waveguides,different transparent materials for direct writing optical waveguides,and the applications of direct writing optical waveguides were reviewed.As is summarized,the induced refractive index changes are materials related,and also dependent on laser energy,pulse duration repetition rate,polarization,and the scan velocity,etc.The femtosecond laser micromachining technique has extensive application prospects in the field of photonic devices.