隨著國人的理財知識快速的增長，投資人也越來越有理財的需求與觀念，共同基金更是一般投資人最主要的投資樣的。然而，投資人面對琳瑯滿目的基金名稱及種類，實在很難憑著有限的資訊選擇適當的基金去投資。本研究站在投資人的角度，縱觀圈內的開放型股票基金市場，使用Excel進行規劃求解將基金建構出一合適的風格指數(benchmark)進行風格分類，做為評估基金績效的標竿，希望從一個正確的基金風格角度來評估基金的績效，試圖給投資人正確的資訊，使投資人能夠依據自己的需求，而進行有效的投資。本研究同時探討相同或不同基金風格之基金其績效表現是否具有差異，結果發現，不論是相同分類或不同分類的基金，其績效並不存在顯著差異。

Accompanying with the availability of financial information, it is easy for the investors to find the opportunities to invest. The mutual fund is one of the most common investment tools. However, investors are often confused by the investment style because of the misclassification. The paper re-examines the investment style of Taiwan open-ended funds by conducting a new style benchmark. After classifying the mutual funds, the performances within peer group and between peer groups are also examined to compare their differences. The results have showed that there is no significant difference within and between different styles of open-ended mutual funds.