Friction stir welding is a recent promising solid state joining technique used to join high strength aluminium alloy. This present work focused to evaluate the effect of process parameters such as tool rotational speed; welding speed and shoulder diameter on yield strength and tensile strength of 6 mm thickness friction stir welded AA7075-0 aluminium alloy joints. As an initial step thermomechanical model was developed using hyper work 14.0 simulation software and simulation process was carried out. Out of different response from the analysis two responses were selected i.e. peak temperature of joint and yield strength. It was observed from the result that the peak temperature of joint is below the melting point of parent metal. After that, experimental work was performed and prepared 27 samples and tensile strength was recorded of all samples.Process parameters were optimized by the full factorial design approach on the basis of high tensile and yield strength. Non-linear regression model was developed to correlate the process parameters to yield strength and tensile strength of joint.