On the basis of a certain theory if we can predict the composition of a specified material in engineering and we can successfully produce the very material instantly according to the theoretical results, this is what the engineering hopes in the practical application. For fulfilling this purpose, the auther had to investigate an appropriate theory and chose few materials to make composites, so that enabling the produced composite materials to be in good agreement with the “object material” given beforehand. In this paper the theory is presented in the three proceeding parts and the results are given in the fourth part. Theoretical calculations were worked out for the composites of the two object materials given in engineering. Composites were produced according to the computational resultes. Experiments were made and their results were satisfactory.