The invention discloses a parameter optimization method for a mixed driving five-rod flower disc planting mechanism. In dry hole disc seedling transplanting, the transplanting work is generally completed by cooperation of seedling-fetching and seedling-planting mechanisms, the design difficulty for realizing seedling-fetching and seedling-planting actions by one set of mechanisms is large. The method comprises the steps of making an initial trajectory of the mechanism according to flower transplanting work requirements, reversely solving an angular displacement rule of the mixed driving five-rod flower disc planting mechanism, and determining control parameters of a constant speed motor and a speed adjustable motor; and optimizing parameters of the mixed driving five-rod flower disc planting mechanism based on a genetic algorithm with a minimum angular acceleration fluctuation of a variable speed motor as a target to obtain a design variable operation result. According to the method, the size of the five-rod mechanism, a position of a rack, an angular displacement needed by a seedling-fetching cam and an angular displacement rotational rule of two driving links are optimized based on the genetic algorithm, the mixed driving five-rod flower disc planting mechanism suitable for full-automatic flower transplanting seedling-fetching and stock-planting trajectory posture requirements is comprehensively designed and provides another design concept for full-automatic flower transplanting.