This paper considers life-testing experiments and its influence of stress factors such as, temperature or electricity loads on the lives of experiment items. Step-Stress test is a special class of accelerated life tests, which allows the researcher to increase stress levels more than normal during the experiment to see the surviving items. The lifetime distribution of the test items is assumed to follow weighted exponential distribution that considered. Different methods for estimating the parameters are discussed. These methods are mainly maximum likelihood and confidence interval estimations which generates narrow intervals to the unknown parameters of the distribution with high probability based on asymptotic normality. Numerical study to illustrate the optimal time procedure using MathCAD (2001) is discussed.