Abstract: Temperature is an important factor in cementing technology. A new table relating cementing temperature and a new temperature measuring method were established by an API group of 13 cementing experts organized in 1984 through 8 year continuous efforts. A API data collecting method of bottom temperature and a new table of cementing and squeeze cementing temperature were recommended in this paper. Using the new API temperature data and regression analysis method, the author established a new mathematical equation of bottom circulating temperature provided to cementing engineers for their rig-site job.