學術上探討外人援助(Foreign Aids, FA)與外人投資(Foreign direct investment, FDI)對經濟成長的直接影響，大多獲致正向關聯的結論。然而，開發中國家的政經體制通常並非十分健全，政府貪污的事件時有所聞。我們發現，貪污與制度因素，對於經濟成長的影響通常是間接的。因此，本研究的目的在於：探討貪污與制度因素間接影響下，外人援助與外人投資對於開發中國家經濟成長的效果。 考量不同貪污程度與制度因素，外人投資及外人援助對經濟成長的影響會有所不同，本研究採用Hansen(2000)門檻模型，跨國分析1996至2011年、非OECD國家共148國樣本。實證結果顯示：在合併的橫斷面資料迴歸中，外人投資對於經濟成長呈現明顯的正向效果；外人援助的顯著性則不明顯。考慮門檻效果之後，我們發現外人投資在貪污程度較低及經濟自由度相對較高的國家，對於經濟成長的影響仍然呈現顯著的正面影響；反之在貪污程度較高及經濟自由度相對較低的國家，外人投資對於經濟成長則沒有顯著效果。外人援助在經濟自由度較高的國家對經濟成長也有很大的助益，但在貪污程度間接影響下，對於經濟成長的表現則尚未有定論。; In most of academic literature, the positive impact of Foreign Aids (FA) and Foreign direct investment (FDI) on economic growth are obtained. In developing countries, however, they often do not have sound political and economic systems. We can always hear about corruption news in these countries. Therefore, we find out indirect impact of corruption and institutional factors that influence economic growth. This paper aims to empirically investigate the effect of FA and FDI on economic growth in developing countries, under the indirect impact of corruption and institutional factors. Considering the possible difference in the relationship between FDI and FA on economic growth for different corruption and institutional factors' level, this study employs the technique of the threshold model to proceed with empirical estimates. Based on a dataset of 148 non-OECD countries over the 1996-2011 period. The empirical results show that stronger FDI stimulate more economic growth in the case of the conventional pooled cross section regression, while FA are not statistical significance. After considering the threshold effects, FDI still have a significantly positive impact on economic growth for countries with lower level of corruption and higher degree of economic freedom, but for countries with higher level of corruption and lower degree of economic freedom, the impact of FDI on economic growth is statistical insignificance. FA are still helpful for economic growth when the countries have higher degree of economic freedom, while the impact is ambiguous under the indirect effect of corruption.