Linear dynamic simulations with one and two degrees of freedom were built from SIMULINK in MATLAB commercial program. Before starting the simulations, initial conditions and system parameters which are mass, spring constant and coefficient of damping are easily inputted by user through each pop-up window, and the conditions for the simulation including time step, analysis methodology and so on can be modified with ease. Also, as soon as the simulations are started, the windows for animations which shows deformed motions dynamically with real time are popped-up and the graphical results are shown in time and frequency domains, simultaneously, The results of the simulations were verified through some examples of textbooks of mechanical vibrations. It was found that the programs would help us to solve any kind of linear dynamic simulation for one and two degrees of freedom.