Instead of the enumeration of amino acid changes in the usual studies of protein evolution, a novel approach is proposed to investigate the amino acid changes focusing on the properties of changed residues. This is illustrated by two analyses: one is the discrimination between adaptive changes and neutrat ones and another is the principal component analysis to assign similar region (s) of the proteins, which seem to be distantly related but cannot be easily detected by the usual similarity search. Throughout these analyses, concrete evidences are provided for divergence pattern and selective mode in amino acid changes, connecting some of the changes with functional changes.