In this paper,a detailed investigation on SU-8based passive-active integrated electro-optic (EO) switch is reported.First, the EO material is synthesized with a simple physical doping process by mixing d isperse red 1(DR1) in SU-8thinner and SU-8(from MicroChem Corp.) solution,and the EO material presents a high EO coeffici ent of 11.5pm/V at the wavelength of 1310nm.In order to reduce the insertion loss of the device,we design and fabricate an inv erted-rib type of hybrid integrated waveguide with DR1/SU-8as the active core layer and SU-8as the passive core layer.After fab ri cating CPW electrode,we pole the device by contact poling method.Under 1550nm wavelength,the switching time and the insertion loss of the device are measured.The measuring results show that the rise time and fall time of the device are 5.6μs and 5.2μs,respectively. And the device has a low insertion loss of 13.8dB,which is reduced by 2.8dB compared with that of the EO waveguide only t aking DR1/SU-8as the core layer.This type of passive-active integrated EO waveguide can reduce the insertion loss effectivel y,and establish foundation for fabricating low loss EO devices and monolithic multi-function integrated devices.