As the key element of the high-temperature sensor, the single crystal fiber has a wide application in the fields of the aerospace, military, electricity and casting. A single crystal fiber drawing system based on the base heating method is proposed. This system is simulated by ZEMAX optical software. The simulation result shows that the high quality ring heat source can be formed in the focus point of the optical system. In order to draw the high-quality single crystal fiber, the mathematical models of the molten zone in the optical system is established and the influences of varies factors on the single crystal fiber are analyzed theoretically. The advantages of the system are incomparable for other optical systems, so it is used widely in zirconia drawing and other high-temperature single crystal fibers.