A multi-level and multiobjective optimization (MLMOO) design method for two-dimensional scramjet inlet was established. Total pressure recovery coefficient, static pressure rise and drag coefficient were selected as performance objective functions to form the multiobjective optimization problem (MOP) of the two-dimensional scramjet mixed compression inlet with 4 external compression ramps and 2 internal compression ramps. The concept of multi-level design was introduced into the inlet performance analysis, one dimensional analysis method and computational fluid dynamics (CFD) method were used on the different stages during the optimization design process. To avoid converging to local optimal solutions and using gradient information which was hard to reach for numerical simulation, a multiobjective hybrid genetic algorithm was employed to find Pareto-optimal solutions in one single run for the present MOP. Following the MLMOO design method, the higher performance scramjet inlet would be worked out steadily.