Automatically mechanical digging has been widely expected for the topsoiling during the growth stage of fruit trees in modern agriculture, due to the high efficiency, low labor intensity, cost saving, and the protection of the roots. In this study, a double-cylinder-driven hydraulic insertion mechanism was proposed to fully meet the working requirements of the whole crawler-type self-propelled machine in the orchard gas explosion subsoiling and deep soil quantitative fertilization. A specific mechanism was also designed to realize a vertical insertion of fertilizing rod into 400 mm or deeper soil. The structure and working parameters of the mechanism were determined for the optimal. A kinematic model of the mechanism was established to explore the kinematic characteristics of the insertion cylinders and components. A Visual Basic 6.0 program was developed to optimize the kinematics of the insertion mechanism. A set of optimized parameters of the insertion mechanism were selected using the human-computer interaction. A motion simulation was performed on the insertion mechanism using ADAMS. Results showed that the motion tracks of the cylinder piston rod point A and the rocker arm hinge point C were the same as the theoretical analysis, indicating that the optimal parameters were fully meet the design requirements of the insertion mechanism. An experimental test was performed on three diameters of rods (30, 35, and 40 mm) under the optimal parameters and the maximum insertion depth, where the insertion time and cylinder pressure were taken as test indicators. It was found that the double-cylinder-driven hydraulic insertion mechanism had fully met the design requirements, including the installation space position of the mechanism, the maximum depth of the insertion rod hole, hydraulic cylinder movement space and piston rod stroke, rocker arm movement and eccentricity, as well as the structural and position parameters. The maximum cylinder stroke was 191 mm when the maximum insertion depth was 760 mm. The insertion time and cylinder pressure increased significantly, with the increase of rod diameter. The rods with three diameters were all fully met the requirements of insertion time and cylinder pressure. The relationship was also determined between the insertion time and the rod speed and cylinder piston speed. The insertion time values were 6.4, 7.5, and 8.2 s for the 30, 35, and 40 mm diameter rod, with the average speed of the rod and cylinder piston of 0.119 and 0.025 m/s, 0.101 and 0.021 m/s, 0.093 and 0.019 m/s, respectively. This finding can provide a strong reference to develop and optimize the gas explosion subsoiling and fertilizing insertion in an orchard.