High temperature superconductors have the characteristics of high current carrying capacity, high mechanical properties and low anisotropy, and are used in applications requiring strong magnetic fields or high current carrying capacity, such as particle acceleration and fusion and other high-field large magnets. When a superconducting conductor is used in a magnetic field, the changing magnetic field will produce a certain amount of AC loss, which will put a burden on the refrigerator and cause a series of negative effects on the thermodynamic stability of the equipment. Here, we report the experimental methods and results for AC losses in three typical HTS conductors, i.e. REBCO CORC, REBCO TSTC, Bi2223 TSTC.