於此篇文章中我們考慮的是一個2 × 2退化的雙曲型守恆律系統,而我們考慮的這一個系統它的第二行方程式缺乏了對時間微分的項。本篇文章主要是研究這個系統的黎曼問題。我們將介紹一種疊代方式去建構這個系統的弱解。其中這些弱解的建構過程中是依據特徵線方法、Rankine-Hugonniot 條件以及分析上疊代方式而獲得。 In this thesis, we consider a 2 × 2 degenerate hyperbolic system of conservation laws whose second equation does not have the term related to the time-derivative of unknowns. The Riemann problem of such conservation laws is studied. We introduce an iteration scheme to construct the weak solutions of the Riemann problem. The weak solutions are obtained based on the characteristic method, Rankine-Hugoniot condition for discontinuous solutions and the iteration to the elementary waves for homogeneous systems.