美國學界現在正興起一股地方政府的歲入多元化（Revenue Diversification）之研究風潮。根據現有文獻的分析探討，歲入多元化的衡量是以市場集中度指標Herfindahl-Hirschman Index（HHI）所修改而成的。而其假設則是認為歲入多元化對於地方政府的收入穩定有著極大的關係，亦即歲入結構愈多元化的地方政府，其收入也就更加地穩定。本研究嘗試著對現有的文獻進行全面性地的探討，並且以我國地方政府從民國90 年到97 年間的四大歲入來源，包括：自有稅課收入、統籌分配稅款收入、補助及協助款收入、以及其他收入，來進行分析探討。本研究的實證結果也顯示，我國地方政府的歲入多元化與歲入穩定存在著正相關性。而這樣的結果也說明了地方政府太過於依賴單一稅收來源可能會危及到其歲入結構之穩定。由於我國大部份的地方政府過於依賴府際移轉之收入，也使得歲入多元化的政策目標受到了考驗。因此，本研究也建議未來地方政府必須在自有稅課收入、以及其他收入方面能夠多加努力並提高其比例，以達到歲入多元化和歲入穩定之目標。

There have been many researches on revenue diversification in the United States, and the concept of revenue diversification has also been considered as a desirable policy goal by many tax experts. In this research, we attempt to investigate the current study on the relevant issues and conduct an empirical study on the relationships between revenue diversification and revenue stability of Taiwan’s local governments. We argue that the more the local revenue sources are diverse, the more the revenue structure is stable. Four major revenue sources of Taiwan’s governments are identified: tax revenue, grant money, revenue from Centrally-Allotted Tax, and other revenue sources. The HHI index was adopted to measure the level of local governments’ revenue diversification during the year of 2001-2008. Total revenue variance was adopted to measure the level of revenue instability of those local governments over the sampled years. Our research results indicate that the level of revenue diversification is positively associated with the level of revenue stability. Therefore, to pursue for a sound fiscal environment and to reduce the risk caused by instable revenue, local governments should not rely on single source of revenue.