本研究主要目的是檢視外資的買賣超資訊是否能為散戶投資人帶來有用資訊，進行跟隨買賣而獲利? 再者，以34家公司樣本為例，觀察外資對某股欲大量買賣超時，經由買賣單的下單積極性分布情形，是否有藉此誤導散戶投資人投資行為的嫌疑?實證結果發現，跟隨外資買進金額買超最大的標的股，確實能為散戶投資人帶來獲利，但若跟隨買超張數最大而買入標的股，獲利幅度會下降。而跟著外資大量賣超而殺出的標的股，不論賣出張數最大或賣出金額最大，散戶投資人未有較高獲利可以獲得。最後，實證發現外資對在欲大量買超或賣超的標的股中，均會以積極性高的下單價格來使其買單或賣單快速成交。但外資大量買超下的賣單比例以及大量賣超下的買單比例下單於積極度最差的價格區間均有高於正常樣本期間的情況發生。 / The main purpose of this study is to examine Taiwan's 34 major companies trading over information for retail investors is to bring useful information to profit following foreign investors’ buy-sell information. Furthermore, this observation of 34 companies to buy-sell ultra -volume, the order distribution of buy and sell would give wrong information to mislead retail investors? The result shows if retail investor follow foreign investors’ step to buy the maximum market share and volume underlying stock can bring abnormal return than market return and industry return, But if retail investors follow foreign investors’ selling behavior not to take extra return from mimic trading behavior. Next, analysis of foreign investors’ trading behavior is consistent or not? We find if foreign investors really want to buy or sell the underlying stock, their buy-order and sell –order will set at the best price to make it a deal quickly , but one the other hand, we find their sell-order and buy-order will set the price which less possible to make this transaction.