Launching of Rocket is a complex phenomenon. There is high chance of failure in such missions. Hence it is necessary to predict the launch path or Trajectory, External disturbances and various other parameters. Numerical Simulation is one such way of predicting launch parameters which helps in taking precautions preventing failure. This Paper presents a platform for simulation of Rocket launch vehicle and control Law validation. The analysis is performed during the Lift-off phase in atmosphere using a mathematical nonlinear dynamic model. Set of six degrees of freedom equations of motion with necessary reference frames and transformations in between them is developed. The Mathematical Model is applied in MATLAB and Simulink simulation which can be easily adjusted for any type of launch vehicle or rocket.