We have demonstrated a highly efficient, high average output power laser based on the optimized resonator made up of multiple Nd:YAG rods. The laser consists of three groups, each of which contains two rods with one quartz 90°rotator between them. By a desirable design of the resonator, the average output power of 1906 W at 1064 nm is reached with repetition rate of 1.1 kHz. The optical to optical conversion efficiency is up to 50.8% with the pulse width 224 μs and it is the highest conversion efficiency of six rods resonator.