Compared with other temperature measurement techniques, the optical temperature measurement techniques have many advantages such as non-contact, real-time and nondestructive features. They have a vital role in nation defense, military affairs and industry production. In this paper, four conventional optical temperature measurement techniques including the laser spectral temperature measurement, the holographic interference temperature measurement, the tricolor temperature measurement based on a CCD and the infrared temperature measurement are presented. Among the above four optical temperature measurement techniques, the infrared temperature measurement is the most widely used technique and its operation principle, method and particular applications are described in detail.