骨骼系統的主要功能包括支撐身體並保護軟組織，還有製造血球與儲存礦物質；骨骼會隨著年齡的增長而成長、老化，當骨骼受傷的時候也有再生長、重塑的能力。當骨骼承受超過機械性的負載則會發生骨骼斷裂的情況，也就是骨折，骨折的癒合牽扯到複雜的組織學，本文的研究重點在模擬長骨骨折後，受到軸向壓應力對骨骼所產生的應力分布進而推測骨折癒合的過程。 本文使用有限元素法的FEMLAB 3.0套裝軟體建立簡單的2D長骨骨折模型並且給定一軸向負載計算各部位的應力值，再使用Excel將取得的資料做整理，然後利用MATLAB 6.5讀入整理好的資料且依據所計算出的成骨指標I，繪出長骨骨折受到負載後軟骨部分的I值範圍圖，再根據得到的圖建立新的2D長骨模型，重複上述的步驟來模擬長骨骨折後癒合的過程。 The main function of the skeleton system is including supporting the body and protecting the soft tissue, still make blood count and store the mineral substance; The skeleton will grow up, wear out with growth of the age, is regenerated long ability reinventing too when the skeleton is injured. As the skeleton bears and exceeds the machinery situation the skeleton will taken place to rupturing in load, fracture that that is to say. The healing of the fracture involves complicated histology. The research of this text focuses on: Pressed the stress and distributed then inferred the situation that the fracture heals to the stress that the skeleton produces by the axial after the simulation long bone fracture. This text uses FEMLAB 3.0 suit software of the law of limited element to set up simple 2D long bone fracture model and give definitely the stress value of calculating every position of an axial load. In order to get osteogenic index I, data from Excel files are calculated by using MATLAB 6.5. Then, according to osteogenic index I, the figure of cartilage's I value will be shown. Thus, the 2D model of long bone can be built from the I value range of cartilage. Repeat above-mentioned steps to simulate the course that the long bone fracture healing.