Abstract: Bhattacharyya and Soejoeti (1989) proposed the TFR (Tampered Failure Rate) model for step-stress accelerated life tests. On step-stress completely accelerated test occasions, this paper points out that the strategy provided in 1, 2 and 5 for seeking parameter estimates under a normal stress using the usual regression analysis is unreasonable. And the paper also offers a method of estimating parameters under a normal stress.