This invention provides a novel lightweight rocker arm frame and a forming process of a curved crown part thereof, including two sidewalls and two bottom plates. The two sidewalls are connected through the bottom plates respectively located at two ends. A ball socket protruded upwards and an oil hole are arranged at a bottom plate at one end, and a bottom surface of a bottom plate at the other end is a bearing surface. A pin shaft hole is formed in the middle of each sidewall without the bottom plates. According to the rocker arm frame disclosed by the invention, the strength of the structure can be ensured while light weight is realized. The production efficiency of the rocker arm frame is effectively improved, and the structure of the valve rod supporting position is improved.