Given that the special requirements for optical fiber in ultra-high High Voltage Direct Current（HVDC）systems

the performance analysis of several special kinds of optical fibers for HVDC transmission measurements and control system is carried out.The optical properties such as the core layer/cladding diameter of the optical fiber

refractive index distribution and the characteristics of flame retardant are studied

providing references for choosing specialty optical fibers with preferable cost performance for the ultra-high HVDC transmission measurements and control system in different application environment.The results indicate that the smaller the core diameter of the fiber

the smaller the attenuation value of the fiber at 850 nm.For the applications in ultra-high HVDC transmission and control system

small-diameter fiber（approximately 62.5μm）tends to be used in the field that the amount of data transmission and are large

and the transmission signal bandwidth is specifically required;large-diameter（approximately 200μm）fiber tends to be used in the field that the power transmission is specifically required.