Prism is one of the key components in space and military white light and infrared optical systems, which can achieve higher precision imaging quality in optical systems. Therefore, the processing and detection technology of ultra high precision prism is proposed. Firstly, the tooling materials and processing methods suitable for prism processing are analyzed, and the difficulties and key points of ultra high precision prism processing are pointed out. Then, it introduces the tooling making, prism bonding, processing, detection methods of ultra high precision prism processing, as well as protective measures to prevent damage to prism tooling. Finally, the Schmitt zinc selenide prism with a total height of 35~95mm was processed, and the surface shape was detected with a Zygo interferometer, the surface shape accuracy reached RMS 0.007μm(λ＝632.8nm);The precision goniometer Prismm aster C2000 is used for angle detection, The first optical parallel difference is less than 1″; and the second optical parallel difference is 1.048″ when measured with XQ20-GI plane laser interferometer; Atomic force microscopy Surface roughness 2.9nm.