本研究以台灣五十成分股為研究對象，研究期間為2007年1月至2011年12月為止共五年符合長期投資平均成本以及分散投資風險之概念，本研究使用定期定額與定期不定額不同的投資策略進行研究，而定期不定額投資策略又區分為「反向操作投資策略」以及「順勢操作投資策略」，分別以三種不同策略且不停利不停損之原則進行模擬投資，以每月第一個營業日收盤價進行投資，投資五年結束後分別計算三種投資策略之年化報酬率，並加以統計其年化報酬率是否有顯著差異並比較其優劣程度。研究結果顯示三種投資策略之優先順序為：「反向操作投資策略」為最佳，「定期定額投資策略」次之，「順勢操作投資策略」最差，以上結果提供投資人作為選擇投資策略之參考依據。

This study made use of the data of primary stocks of Taiwan Top 50. And the specific period that this study employed was the period from January 2007 to December 2011, the length of five years in total met the investment concepts of long-term Average cost and Risk Diversification. The study chose Dollar Cost Averaging and Value Averaging, two different investment strategies, as the research objectives. However, there were two sub-objectives under Value Averaging: ＂Contrary Investment Strategy＂ and ＂Trend Following Investment Strategy＂, thus, this study conducted a simulation of three different investment strategies without the interruption of stop-loss and stop-profit. The simulation started the investment from the first business day of each month and set the closing price of the day as investing price, the same pattern of investment kept going up to five years, then calculated separately each strategy's annualized return. The study also run statistic of each annualized return to see whether any significant difference and, meanwhile, compared strategies' advantages and disadvantages. The results show that the best investment strategy is ＂Contrary Investment Strategy＂ followed by ＂Dollar Cost Averaging＂ strategy, and the strategy of ＂Trend Following＂ is worst among strategies. This study will provide the optimal investment decisions for investors in financial markets.