早期對增層現象（F3 layer）的研究大多以模擬與電離層探測儀定點觀測為主，而以磁赤道附近的測站才能看到增層現象，故其物理機制主要為E×B 漂移與子午向中性風。本論文是利用福衛三號掩星觀測來記錄2006年9月至2007年8月間的增層現象，其中增層現象分為foF2<foF3與foF2>foF3兩種類型，並分別統計一年當中兩類型增層現象其foF3、hmF3月平均值，全球分佈地點與分佈時間點，由統計結果來看其季節效應。並將每天發生的增層筆數與F10.7、Kp參數做比較。最後將foF3、hmF3月平均值與1995年Fortaleza(38°W, 4°S) 電離層探測儀定點觀測來做比較，來看季節效應是否吻合。並將兩類型增層各別分佈時間點來與早期模擬比較，看是否有相關性。 The earlier study of the additional layer (F3 layer) was primarily focused on simulation and stationary observation from ionosonde. The additional layer phenomenon can only be observed from the station near magnetic equator, and so the physical mechanism is concluded mainly by the E×B vertical drift and meridional neutral wind. In this paper we use FORMOSAT-3/COSMIC radio occultation observations to demostrate the additional layer from September 2006 to August 2007. There are two types of these additional layers, which are foF2<foF3 and foF2>foF3. We have computed two types of monthly averages of two type foF3 and hmF3 values, and demostrate their global distributions and happening time. The results can be used to obtain the seasonal variations. And we have verified the relationship of the additional layer to the parameters of F10.7 and Kp. Finally, the monthly averages of foF3 and hmF3 are compared with the ionosonde observations at Fortaleza (38°W,4°S). The respective distribution time of these two types of additional layer is also compared with earlier simulation to see if they are relative.