This paper, on the basis of "Expected Utility Theory", employs the a new method called "the Derivate course between two Logarithmic variable with S-shaped relation" (DLS hereafter) to testify the Kuznets.

This paper oppugns the analysis of expect utility theory,uses prospect theory to interpret insurance,and points out that insurance buyer is risk seeking when facing gains and risk averse when facing lose.

Based on expected utility theory,the method combines stochastic dominance relation and current PROMETHEE Ⅱ method.

Surveying the theory development of behavior decision making under uncertainty,and reviewing expected utility theory,Simon\'s bounded rationality,prospect theory and ecological rationality,a trend analysis of the theory development of behavior decision making under uncertainty can be made clearer,which developed from Absolute rationality to bounded rationality to ecological rationality.

The result shows that the difference of the risk aversion tendencies makes the big firm s expected utility of the R&D return higher than the small firm s, which causes the merger incentive.

The author makes a cost-benefit analysis of the discredit from a static and dynamic perspective respectively by using the above assumption and the frame of the expected utility theory.