Abstract: Aiming at the problems that it is difficult to separate dandelion seeds from the pappus, and the separation process involves a large amount of labor and high labor costs, the two-stage dandelion seed and pappus separation machine is designed. The overall machine structure consists of a primary separation unit, a secondary separation unit, a negative pressure impurity separation device, a transmission unit and a feeding port. In this article, the structural design and calculations for the sieve screens of the primary and secondary separation units are carried out. The design parameters are determined as follows: the height of the primary conical sieve screen is 277 mm, the base length is 320 mm, the number of top ring sieve holes is 87, and the number of bottom ring sieve holes is 185. The secondary perforated sieve has a diameter of 520 mm with a total of 6 928 sieve holes. The experiment is conducted with the feeding amount and brush speed as the experimental factors, and the threshing rate and damaged rate of dandelion seeds as the experimental indicators. The optimal working state of the separator is obtained as follows: when the brush speed is 320 r/min and the feeding amount is 0.003 7 kg/s, the threshing rate is 87.6% and the damaged rate is 2.8%. The overall structure of the dandelion seed and pappus separation machine is reasonable, and the operating condition is stable, which can meet the design requirements.