Height determination for Mt.Everest has been carried out 5 times,1966,1975,1992,1998,and 1999 respectively.since 1960 s.The analysis and recomputation of measurement results obtained in the height determination mentioned above are made in recent years.The continuously decreasing trends for the height of snow top at the summit of Mt.Everest are found,and the possible relationship with global warming is discussed.The height for Mt.Everest in global height datum is also presented.