Driving two new formulas for p(xy), the stress- strength reliability function, and estimating the formulas by Bayesian and non-Bayesian methods using different densities of weibull and gamma. The non-Bayesian methods are MLE and MOM and the Bayesian methods done under Squared error Loss function by different priors which are Jefferys non-Informative, Extension Of Jeffery and Inverse Gamma prior Distributions.