The present invention provides a kind of artifucial limb structure at one's knees of field-replaceable unit,It is comprising support component,It supports and adjusts length with what,First assembly is arranged in the side of support component,The second component is arranged in one end of support component,Shell is distinctly arranged in first assembly and the second component again,The aesthetics of appearance of the present invention is promoted,Setting is arranged part below support component,It is arranged part and is arranged what again and plug part,The end component of the affixed lower section setting of part is plugged,Part and the connection for being arranged part are plugged using releasing,End component is set to separate the effect of reaching field-replaceable unit with support component,Artifucial limb is set to adapt to the various demands of user,Also using it is replaceable the effect of so that end component is had spare unit,Prevent end component damage,The situation for making artifucial limb be difficult to walk.本發明提供一種可更換部件之膝下義肢結構，其係包含支撐組件，其用於支撐及調整長度，支撐組件之一側設置第一組件，支撐組件之一端設置第二組件，第一組件及第二組件再各別設置殼體，提升本發明外觀之美觀性，支撐組件下方設置套設件，套設件再套設於插設件，插設件固接下方設置之末端元件，利用解除插設件與套設件之連接，使末端元件與支撐組件分離達成可更換部件之功效，使義肢適應使用者之各種需求，也利用可更換之功效使末端元件有備品，預防末端元件損壞，使義肢難以行走之狀況。
