Aiming to address the issues of low efficiency in manual harvesting and high damage rate in mechanical brushing harvesting of marigolds, an automated marigold harvesting platform with a clamp-feed type design was proposed. The structural design and testing of the harvesting end were carried out to meet the harvesting requirements. Through field tests of the handheld harvesting end mechanism, factors affecting the damage rate of marigolds were identified, including the center distance of the synchronous pulley, the rotation speed of the synchronous pulley, and the harvesting angle. A three-factor, three-level central composite design and response surface analysis were used to study the interaction effects of these factors on the harvesting success rate. A quadratic regression model was established with harvesting damage rate as the response variable, and the significance of each factor on the harvesting success rate was ranked. By optimizing the factors with the damage rate as the objective, the optimized parameters for the center distance of the synchronous pulley, the rotation speed of the synchronous pulley, and the harvesting angle were determined to be 56mm, 200r/min, and 30°, respectively, with a predicted damage rate of 6.59%. Three sets of validation tests were conducted with the optimized parameters, and the results showed that the end harvesting device could effectively complete the marigold harvesting task, with damage rates of 8%, 4%, and 8%, respectively. The relative error between the test values and predicted values was less than 4%. A marigold harvesting device with a mechanical arm module was designed based on the actual working environment, its design closely focused on the growth characteristics of marigold and the core requirements of precision and efficiency for harvesting operations. It can accurately and quickly move the end effector and locate the target marigold position to complete the picking action with stable support and drive. On this basis, a test platform was built, and harvesting tests were conducted. The success rate of the harvesting tests was 93.01%, confirming the feasibility of the clamp-feed type marigold harvesting device.