In this research, draft requirement of subsoiler tine plus fuel consumption, slippage, drawbar power, traction efficiency and overall energy efficiency of MF??? and JD???? tractors at four speeds of ?.?, ?.?, ?.? and ?.? km/h and two depths of ?? and ?? cm were compared. Tractor type, speed and depth plus interaction effects had a significant effect on all parameters other than draft and drawbar power. Generally, JD???? showed a better performance as the increase in speed from ?.? to ?.? km/h caused the increase of draft, fuel consumption, slippage, drawbar power and overall energy efficiency in two depths of ?? and ?? cm of ?, ?, ??, ???.? and ??%, respectively but caused the decrease of traction efficiency of ??.?%. Furthermore, ?? cm increase in depth caused the increase in draft, fuel consumption, slippage and drawbar power of ??.?, ??.?, ??.? and ??.?%, respectively but caused the decrease in traction efficiency and overall energy efficiency of ?.? and ??%, respectively. The results of optimization of studied parameters using response surface methodology (RSM) show that depth of ??.? cm and speed of ?.? km/h resulted in the optimized condition about the performance of the tractor-subsoiler set.