The photoelectronic properties of the high-temperature superconductors are analyzed by using a free electron laser (FEL). The method is a type of photoelectron spectroscopy and called a free electron laser internal photoemission. It is found that when the high-temperature YBa2Cu3O7-x film is irradiated by FEL, the photocurrent is induced in an unbias condition and its amplitude increases with increasing of the FEL power. The temperature dependence of the photocurrent is also investigated.
