本篇論文旨在從優選理論（Optimality Theory）的架構觀點分析海陸客語中 的三個音韻現象：變調（Tone Sandhi）、介音（Pre-nuclear Gliding）及音節連併（Syllable Contraction）。 　　在變調方面，由於海陸客語中上聲與陰入聲助數詞不因環境而變調，在利用之前文獻解釋時必須另外設定條件來說明海陸助數詞的特殊變調行為，本文建議利用優選論的制約來分析，本文所提出的一組制約，可以成功的解釋海陸客語中的上聲與陰入聲變調現象。 　　在介音方面，本文選擇以端木三所提出的音節結構為海陸客語音節結構，因為海陸客語中介音所呈現的行為較似起首子音的次發音特徵，因此本文亦提出了一組制約解釋海陸介音在音節中的歸屬。 　　在音節連併方面，本文檢驗了之前文獻所提出的方法，發現無法全面解釋海陸音節連併的現象，因此，提出一組關於音段與聲調的連併之制約將海陸音節連併現象以優選理論呈現。 　　本文是第一篇嘗試以優選理論解釋海陸客語音韻現象的研究，希望能從不同於之前文獻的角度討論海陸客語音韻的問題。之前理論運作的缺陷與不足，在本文的分析下，均可以成功的以優選理論之制約層級來說明。 / This thesis aims to explore three issues in Hai-lu Hakka Phonology in terms of Optimality Theory (OT). The three issues are tone sandhi, pre-nuclear gliding and syllable contraction. 　　Hai-lu Shang Toned and Yin-ru Toned numerals preserve their base tones in any case. Thus, previous studies would need to add an additional condition for the special tone sandhi behaviors of Hai-lu numerals. This thesis offers a set of OT constraints to explain tone sandhi in Hai-lu. The OT constraints can successfully operate Hai-lu tone sandhi without additional conditions. 　　Pre-nuclear glides in Hai-lu behave like the secondary articulations of the onsets. This thesis suggests Duanmu's (1990) syllable structure for Hai-lu syllables. A set of constraints are proposed to explain the pre-nuclear gliding in Hai-lu syllables. 　　The approaches previous studies suggest for syllable contraction are not across-the-board in Hai-lu. Thus, a set of segmental and tonal constraints are proposed to explain Hai-lu syllable contraction. The OT constraints operate syllable contraction in Hai-lu without difficulties. 　　This thesis is a pioneering study which aims to examine Hai-lu phonology in terms of OT. With OT constraint rankings, this thesis explains the remaining problems from previous studies successfully.