The invention discloses a front anti-collision beam assembly lightweight designing method based on an independent assessment working condition and solves the problems that influence of various collision working conditions on performance of a front anti-collision beam assembly is considered insufficiently and verifying of the performance is only conducted in a whole vehicle at the stage of structural improving and lightweight designing of the front anti-collision beam assembly. The method includes steps: 1), selecting various collision working conditions: selecting collision working conditions various in form and capable of comprehensively reflecting anti-collision performance of the front anti-collision beam assembly; 2), determining a lightweight design performance target of the front anti-collision beam assembly: determining a performance target of the front anti-collision beam assembly on the basis of the anti-collision performance of the whole vehicle in each collision working condition; 3), establishing the independent assessment working condition of the front anti-collision beam assembly and verifying effectiveness of the same: establishing the independent assessment working condition of the front anti-collision beam assembly, and verifying the effectiveness of the independent working condition; 4), performing lightweight designing on the front anti-collision beam assembly on the basis of the independent assessment working condition: using the determined performance target of the front anti-collision beam assembly as a constraint condition and the independent assessment working condition as a carrier to perform lightweight designing on the front anti-collision beam assembly.