For many years, engineers, have been using proggaming language for calculating their designs. that languages are fortran, C++, basic and other console program and also visual basic, visual C++, delphi, java, and other GUI based program. after they have finished, sometimes they found inappropriate result, so they must re-calculate again. we could not only say that our design was right or wrong, designer must know what is the best result from our calculation based on nice, comfrot, speed, smooth, and safety. in this paper i try to choose which progamming language that support both numerical computation and simulation at the same time. coil spring design with problem of differential equations, transfer function in lapace variable and simulation for the step response, impulse response, root locus and bode diagram is adequate for comparing fortan, MATLAB, delphi and visual basic, good result (by expert choice 2000 sofware) is MATLAB 7 R-14 with analytic herarchy process (AHP) technique, and with MATLAB i try to show the simple coil spring design of two degrees of freedom suspension system and at same time simulate the result by step response, impulse response, root locus and bade diagram. of course, the using of grapic user interface (GUI), tool boxes and the m-files for supporting the numerical computation is a must.