This work deals with Kumaraswamy distribution. Maximum likelihood, Bayes and expansion methods of estimation are used to estimate the reliability function. A symmetric Loss function (De-groot and NLINEX) are used to find the reliability function based on four types of informative prior three double priors and one single prior. In addition expansion methods (Bernstein polynomials and Power function) are applied to find reliability function numerically. Simulation research is conducted for the comparison of the effectiveness of the proposed estimators. Matlab (2015) will be used to obtain the numerical results.