The strong clear air turbulence is the outburst gale which takes place at the seashore area in winter and often causes the disastrous nautical accidents.The physical causation and forecast of the strong clear air turbulence according to atmospheric circulation characters are discussed.It comes to the conclusion that the strong clear air turbulence is caused by the energy transition of the baroclinic atmosphere,the activity of northwest jet and the momentum downward transfer.On the basis of these analyses,the forecast idea and method of the strong clear air turbulence,are brought forward.