Literatures indicate that B/M ratio contains characteristics of growth opportunity, persistent biases and transitory lags. This research verifies the relationship of R&D investment and B/M ratio. The findings show that benefits due to R&D investment are realized in the coming years. Thus, the firm's R&D expenditure is capitalized and R&D asset is estimated. Based on empirical analysis of panel data method, ANCOVA, and portfolio analysis, this study finds that the corporations with lower B/M ratio, the effect of required rate of return of R&D is smaller than the effect of growth opportunity. The implication of the empirical results suggests that B/M ratio may explain stock returns of higher B/M corporations, while R&D investment may explain stock returns of lower B/M corporations.