The study of “The Explanations of Stock Prices Using Net Profit and Cash Flow Operating” is an empirical research which utilized the data from the listed companies regarding industrial product groups. The companies consisted of variety of business, for example, automotive and auto parts, industrial and machinery, packaging, paper and printing, petrochemical and chemical products and steels. The purposes of this research is 1) to examine the relationship among the net profit, stock prices and the overview of industrial product groups 2) and to study the relationship among cash flow operating, stock prices and the overview of industrial product groups. Multiples Regression Analysis was applied in order to investigate the significance of the independent variables which were the net profit and the cash flow operating. It was also used to find out which variable is suitable for explaining the stock prices in each business sector and the overall of industrial product groups. The results showed that there was a significant relationship among stock prices, net profit and cash flow operating. That is to say, net profit can be used to describe the prices of stock. In terms of the automotive, industrial and machinery, petrochemical and chemical product, and the overall of industrial product groups seemed to tell the prices more accurately than the cash flow operating. However, in packaging and steel business, cash flow operating tended to predict the prices more effectively than the net profit one.