This paper describes the distance measurement of optical surface based on optical coherence tomography (OCT). A single-mode fiber-designed OCT system is developed which consists of a near infrared light source,a Michelson′s interferometer and optical heterodyne detection. Distance testing experiment of range cover glasses is carried out by using this OCT system. The result shows this measurement system has the features of high speed(500 Hz),high sensitivity(6.7 μm),high precision(about 2.07 μm),and it is a non-contact type. The designed fiber system is compact and flexible,and it has great potential in optical material testing,optical manufacture,and optical alignment.