The concealment，cumulativeness，hysteresis，complexity，and cross-administrative regionality of soil pollution render the delineation of boundaries for regional collaborative governance of soil pollution a complex systematic project.At present，China’s regional collaborative governance of soil pollution faces challenges due to ambiguous multiple boundaries， including scope boundaries，subject boundaries，and behavior boundaries，which directly affect the effectiveness and sustainability of such governance.Grounded in the theories of collaborative governance，administrative self-restraint，and limited government，this study proposes specific approaches to improve the normative system and clarify scope， subject，and behavioral boundaries.By constructing a scope boundary model that prioritizes administrative boundaries as the foundation，functional boundaries as the dominant factor，and geographical boundaries as the auxiliary element，establishing a triangular coordination model of multi-subject governance involving government leadership，market participation，and public engagement，and adopting a behavioral boundary clarification method centered on necessity and appropriateness，this research aims to provide scientific guidance for boundary delineation in regional collaborative governance of soil pollution.These efforts seek to advance cross-administrative regional collaboration in soil pollution prevention and control，thereby fostering continuous improvement in ecological environment quality.