The polymer waveguide electro-optic (EO) devices play a key role in improving the optical network bandwidth and capacity. A quasi-rectangle EO waveguide based on organic/inorganic hybrid material (OIHM) is designed and fabricated. SiO2 is adopted as the lower cladding. The ultraviolet photo-resist SU-8 is used as the guiding core. The chromophore of dispersed red 1 (DR1) doped OIHM is used as the EO active layer. Through optimizing the parameters including antenna power, biasing power and O2 flow rate of inductively coupled plasma (ICP) etching, SU-8 can be applied as the guide core and etching mask at the same time. By the traditional semiconductor processes, the quasi-rectangle EO waveguide device is successfully fabricated. Under this condition, the transmission loss is -3.5 dB/cm.