本文主旨是在使用有限元素法（包括第一、第二、第三限元素法）對一個燃燒熱能模型之邊界值微分方程式，求其數值近似。 　　首先，由這些方法可到一些聯立方程式。其次，對各種有限元素法分別去分析它們解的存在性和誤差估計。最後，舉一個實例來討論其解的變化情形並圖示它們。 　　換句話說，從本文所得到的方程組或圖形，將可求得此微分方程式的解與個數。 / The main topic of this paper is to usee the finite element methods (contain F.E.1, F.E.2, and F.E.3) to find the numerical approximation of a model for thermal ignition. First, we obtain a system of equations for those methods. And then, we analyse the existence and the error estimate of solutions with each method. At last, we give an example to discuss those results and graph them. In a word, from those equations or graphs which are given in this paper, we will get the numerical solution and the number of solutions.