An experiment platform for reciprocating hydraulic flushing and digging device for lotus roots was designed to solve the problem of low operating efficiency and serious leakage existing in the fixed flushing method of traditional hydraulic digging nozzles for lotus roots.Fluent simulation was used to conduct one-factor experiments on the shape of the nozzle and obtain the cone-column shape as the optimal shape.EDEM-Fluent coupled simulation was used to carry out L₉（3⁴） orthogonal experiments on the key dimensions and working parameters of the nozzle and obtain the optimal parameters for the nozzle being a diameter of water outlet of 15 mm，a height of mud clearance of 50 mm，and a jet angle of 30°.The integral method was used to theoretically analyze the trajectory and flushing area of nozzle.The optimal forward speed and swing speed of the nozzle in theory were calculated with Matlab to be 17.3 and 130.7 mm/s.The performance of a single nozzle flushing silt was tested based on the test platform of reciprocating hydraulic flushing and digging device.The results verified the reliability of key dimensions and working parameters of the nozzle obtained from the simulation experiments.A Box-Behnken center combination performance test was conducted to investigate the comprehensive effects of jet angle，forward speed，and swing speed on the digging rate of lotus roots.The results showed that the digging rate of lotus roots was the highest when the jet angle，the forward speed，and the swing speed was 27.4°，10.6 mm/s，and 191.1 mm/s.The digging rate of lotus roots in the simulation and the test platform was 93% and 91%.It will provide reference for studying the principles of harvesting machinery and hydraulic flushing of lotus roots.