Abstract: It is often used the method to discuss the property of solution of differential  system  in  Liapunov  function.It  have  been  proved  that  the  me- thod  is  effectively.This  paper,using  a  new  proved  inequality  and  Lia- punov  function,we  consider  a  few  classes  of differential  difference  equa- tions  and present  some  sufficient  conditions  of the  trivial  solution  of the system  are  exponential  stability.