An X-ray photographical auxiliary device for knee joint which includes a base, which is provided with a height-adjustable lifting platform, wherein the lifting platform is provided with an upper pivoting portion for pivotally disposing a placing frame, and for being positioned after pivoted at an angle； a leg fixing device, which has a longitudinal slide rail slidably disposed on the placing frame, and a transverse slide rail slidably disposed on the longitudinal slide rail, wherein the transverse slide rail is provided with two positioning rod sets, and a width-adjustable leg accommodation space is formed between the two positioning rod sets； and a pedal, which is disposed at the bottom end of the placing frame with an adjustment mechanism for allowing the feet to step thereon, wherein the adjustment mechanism is configured to adjust the distance of the pedal relative to the placing frame.一種膝關節之X光照射攝影輔助裝置，包括有一底座，其設有一可調整高度之升降台，此升降台設有一上樞接部以樞設一置放架，且可在樞擺一角度後加以定位；一雙腿固定裝置，其具有一設於置放架上之縱向滑軌，以及一滑設於縱向滑軌上之橫向滑軌，其中橫向滑軌上滑設有二定位桿組，兩定位桿組之間形成有一寬度可調整之雙腿容置空間；一踩踏板，其以一調整機構設於置放架之底端而可供雙腿踩踏，此調整機構可調整踩踏板相對置放架之距離。
