The invention relates to a method for measuring centrodes of a knee joint. Primarily, a subject sits on a seat portion of a base, and movable plates are moved and adjusted up and down according to the leg length of the subject put on a measuring board of a measuring seat in front of the seat portion so that the subject can put one leg to be measured on the front of the measuring board and the foot on a foot pedal. The power source is operated by the subject to rotate the measuring seat to rise up to the same angle position of the seat portion to proceed with zeroing, and then the power source is operated to rotate the measuring seat to descend to the largest angle at which the knee of the subject can be bent. During this procedure, the data measured by the first angle encoder, the length measures and the second angle encoder can be processed with the conversion to calculate the related data of the centrodes of the knee joint of the subject. Accordingly, it can proceed with non-invasive measurement without radioactive hazards, and it has higher precision to obtain the measuring result immediately, so as to increase the practicability and efficiency for the whole implementation.本發明有關於一種膝關節極心線量測方法,其主要係令量測者坐於底座上之坐椅部,且依量測者腳部長度於坐椅部前端量測座之量測板上下移動調整移動板之位置,使得量測者即可將待量測之一腳置於量測板前端,且令腳掌踩踏於腳踏板上,由量測者操作讓動力源帶動該量測座轉動上升至與坐椅部同一角度位置進行歸零,再操作令動力源帶動量測座轉動下降至量測者膝蓋所能彎曲之最大角度,於此過程中即能藉由第一角度解碼器、長度量測器及第二角度解碼器所量測到的數據進行換算,而可算出量測者膝關節之極心線的相關數據;藉此,以達到非侵入式進行量測,且無放射性危險存在,並於量測上精密度較高,可立即獲得量測結果,而在其整體施行使用上更增實用功效特性者。(1)‧‧‧底座(11)‧‧‧坐椅部(2)‧‧‧動力源(21)‧‧‧傳動輪(211)‧‧‧連動件(3)‧‧‧量測座(31)‧‧‧驅動輪(32)‧‧‧量測板(33)‧‧‧第一角度解碼器(34)‧‧‧長度量測器(35)‧‧‧移動板(36)‧‧‧腳踏板(37)‧‧‧第二角度解碼器