Aiming at the phenomena of imperfect filling of substrate leading to shallow and exposed root system during potting and transplanting of non-woven containers, and slow transplanting efficiency due to low automation degree of transplanting machine, a fully automated secondary transplanting device based on non-woven containers was designed in combination with the growth characteristics of young forest seedlings. The mechanical claw installed on the transplanting arm realized XYZ three-dimensional space transplanting operation without dead angle, and the transplanting efficiency was improved by alternately picking up seedlings through the two-way assembly line platform. Through the design and force analysis of the key components of flexible gripper, the influence of deformation coefficients of seedling substrate under different gripper pin spacings was explored, and the motion state of transplanting arm was optimized through kinematic analysis by combining the RecurDyn rigid-flexible coupling simulation. Considering the key factors affecting the success rate of transplanting, the secondary filling force rate, moisture content of seedling substrate and clamping pin spacing were determined as the test factors. Taking 60pin capillary seedlings as the test object, the relevant parameters were derived from a one-factor test, and a multifactor orthogonal test was conducted to determine the optimal operating parameters of the automatic secondary transplanting device for non-woven container seedlings. The test results showed that when the force rate of the secondary filling mechanism was 83.51%, the needle spacing was 19.66mm, and the water content of the seedling substrate was 33.45%, the transplanting success rate was 95.29%, which was basically the same as the results of validation test (95.33%), and the requirements of high-speed and high-efficiency transplanting were met, which provided a reference for the field of secondary transplanting of non-woven containerized seedling in forest trees.