Combined with the design process of a support project in Handan city when dealing with the change of the depth of the foundation pit, in view of the different stress characteristics of the front and rear rows of the double row piles, the design idea of the long and short combined double row piles is proposed. Through the analysis and calculation of various working conditions by the straightening software, a more economical solution of the long and short combined double row piles is obtained on the premise of safety and reliability and the implementation of the current conditions of the foundation pit. The practice results show that the long and short combined double row pile support system can give full play to the different functions of the front and rear rows of piles, and can be used to solve the problem of insufficient embedded depth of existing support piles after the change of foundation pit depth, and can also be used in the normal foundation pit support design.