With the rapid application of computers, a number of techniques of multivariate analysis have been developed and widely used in the fields of behavioral sciences. Unfortunately, many researchers who are concerned with data analysis often think that it is too difficult to determine the best technique for the given data, since they consider various techniques to be quite varied in its mathematical structure. In view of this, we try to describe various techniques of multivariate analysis in terms projection operator in order toclarify the mutual relationships among various techniques by introducing the conception of generalized coefficient of determination(G.C.D.). As a result, we can prove that coefficients of determination such as correlation ratio, squared multiple correlation and Maharanobis generalized distance are represented as special cases of G.C.D.