Abstract: In view of urgent demand for straw bale net detaching and problems such as low automation and efficiency of existing net detaching methods, a straw bale net detaching device was designed based on feasibility tests of straw bale cutting performance．This device realized automatic and rapid net cutting, detaching and transfer functions．It comprised a net cutting mechanism, bale transfer mechanism, net detaching mechanism, frame and PLC control system．Three-dimensional modeling was carried out using Solidworks．Simulation static stress analysis was conducted on key components．A test bench control system was built．Taking straw round bales as test object, and idler roller rotation speed, idler roller rotations count, and net detaching roller rotation angle were taken as test factors．Bale net residual rate and bale detaching time were taken as evaluation indicators．A box-behnken design（BBD）response surface experiment was carried out using Design-Expert 13．Experiment results were analyzed through variance analysis, response surface analysis, and multi-objective optimization．Results showed that optimal parameter combination was 53 r/min idler roller rotation speed, 3 idler roller rotation cycles, and 51° net detaching roller rotation angle．Under optimal parameter combination, net bale residual rate was 0.25% and detaching time was 23.3 s, indicating small relative deviations．A reference for research and development of round bale net detaching device was provided．