An optimization model for load sensing hydraulic excavator was established, in which the largest flow areas of hydraulic multi-way valves were taken as main design variables and working cycle time was taken as the main objective while the other design requirements were used as main constraint conditions. An optimizing example was presented. The result showed that the cycle time was reduced from 14.04 s to 12.61 s. Meanwhile, most of the other performance indexes were also improved. The largest optimized digging force of bucket cylinder and arm cylinder were increased by 4.38 kN and 3.61 kN, respectively. The largest digging height and the largest digging radius were increased by 189 mm and 37 mm, respectively. The generalized optimization of entire system and overall performance for excavator was realized.