To address the shortcomings of the Harris Hawks Optimization (HHO) algorithm in solving complex high-dimensional optimization problems with a slow convergence speed, low accuracy, and the high likelihood to fall into local optimum, a Mixed Harris Hawks Optimization (MHHO) algorithm based on the pinhole imaging strategy is proposed. Firstly, the pinhole imaging strategy is used to enable the Harris' hawks to approach the optimal solution faster and accelerate convergence. Secondly, the spiral parameter is introduced into the exploration phase to help the searching paths of the Harris' hawks more diverse, and improve the global search ability of the algorithm. Finally, the greedy strategy of the aquila optimization algorithm and the position update strategy of the flower pollination optimization algorithm are embedded in the Article Title exploitation stage to make the algorithm jump out of local optimum effectively. To verify the effectiveness of the proposed MHHO algorithm, it is compared with the classical HHO algorithm and 16 other state-ofthe-art algorithms, and extensively tested on 23 well-known benchmark functions, the IEEE CEC2017 test set, and three complex constrained engineering optimization problems. The test results show that MHHO outperforms the classical HHO algorithm and other 16 algorithms, and has a faster convergence speed and higher convergence accuracy.