Abstract: Q vector, helicity, potential vorticity and its inversion are advanced diagnostic tools of synoptic meteorology in modern times. Qvector is taken as an effective method to estimate vertical motion. Helicity depicts dynamic feature of fluid that is rotating while moving alongthe rotating direction. Potential vorticity comprehensively describes the thermodynamical and dynamical characteristics of atmosphere, and ithas the properties being conservative and invertible. Potential vorticity inversion is the procedure that the corresponding wind, temperature,geopotenrial height and so on can be derived when potential vorticity and boundary conditions are given with a premise of balanced motion.The mechanism and prediction of torrential rainfall in typhoon is always one of important issues in atmospheric science and one of difficultquestions in operational forecasting. The applications of the above diagnostic methods in past research on torrential rainfall associated with typhoonis thoroughly reviewed in this study, along with prospective applications of these tools in the future.