THz band is a radiation area full of scientific value but still needs further reearch.THz source is the key device for its application.Also,it is the forefront issues in the THz technology fields.The THz source via parametric process has being in depth research in recent years because of its merits of high nonlinear conversion efficiency,easy to miniaturize and operate in room-temperature with wide tunable frequency.This THz generation mechanism via parametric process and some influencing factors of the radiation are introduced.Also,recent research progress in this field is discussed and the future of this generation method is forecast.