Based on the positive relationship between traders’asset allocation and the stock price volatility found in the behavioral financial experiments,the paper builts a mathematical model of traders’assets with funds taken into our consideration.As a consequence,funds have double effects on the stock market.At the beginning of issuing funds,funds will lead to market volatility;when the funds assets reach a certain quantity,funds will play the role of stabilizing the market.In addition,huge scale funds should be stopped because it may bring large volatility to the stock market.

For the effective analysis of investors' behaviors and professional practice teaching of securities investment,the undergraduate simulation exchange is designed with independent matching system,versatile functions and convenient operation,which framework can be divided into the following three parts: access interface,independent matching system,transaction account management and experimental operation control system.The independent matching system is the core of the simulation exchange,which is a prerequisite for the completion of all experiments.Through the acquisition and processing of experiment data,the characteristics of investors' behaviors can be analysed.Simulation exchange can also be applied to the securities investment professional practice teaching and stock simulation game.All the students who participate in professional practice teaching and stock simulation game are the test objects of behavioral finance experiments.

In this paper, making the seventy-five countries as simples, we first use computing methods of Passche weighted and simple average to present an index design method of change rate based on formation principle of index, and then work out stock price indexes of Asia-Pacific, America and Europe, respectively. We draw up a unified index of global stock market according to the three regions. Finally, we empirically make a analysis of the correlation, between world stock index and region stock index. We use Granger causality method to test the causal relationship between world stock index and GDP. The results indicate that world stock market is the ＂barometer＂ of world＇ national economy.

Based on the experiments carried out in the simulated exchange independently developed by the Financial Engineering Laboratory of University of Science & Technology Beijing, this paper researched the impact funds have on the stock market after certifying the positive relationship between traders' asset allocation and the stock price volatility. According to the positive correlation, the paper built a mathematical model of traders' asset when funds are taken into our consideration. In the model, it certified the impact funds have on the stock market by computer simulation. As a consequence, funds have double effects on the stock market. When the funds assets account for less than 50% of total market assets, funds will lead to market volatility, when the proportion is more than 50%, funds will play the role of stabilizing the market. In addition, huge scale funds should be stopped because it may bring large volatility to the stock market. We recommend that it is good to repeatedly issue small scale funds instead of huge scale funds. Last but not the least, gradually increasing the quantity of issuing funds can not only avoid large market volatility, but also let the funds quickly play the role of stabilizing the stock market.