In this paper, inverse Weibull (IW) distribution with the step-stress model and progressive type-II censoring data are considered. The maximum likelihood and Bayesian estimation are discussed for the distribution parameters and the acceleration factor. The outline criteria in Bayesian approach are settled under utilized non-informative and gamma informative priors under balanced squared error and balanced linear-exponential loss functions with the help of MCMC method. Finally, the numerical example and simulation study are constructed to assess the obtaining results.