Objective: Inquiry into the correlation between residues (SO2) and the effective contents of imperatorin and oxypecedanin in Angelica Dahurica Radix after sulfur fumigated to provide scientific bases for formulating the scientific, rational, objective, controllable standards of sulfur dioxide limits. Method: To dynamic determine the residue of sulfur dioxide by appendix in 2010 version of 'Chinese Pharmacopoeia’ and the content of imperatorin & oxypeucedanin by HPLC. To correlation analyze the residue of sulfur dioxide and effective content by curve regression. Result: Residues (SO2) in samples without sulfur-fumigated is lower than sulfur-fumigated samples and imperatorin & oxypeucedanin in samples without sulfur-fumigated is higher than sulfur-fumigated samples. As the amount of sulfur and fumigating time increase, residues (SO2) increase and imperatorin & oxypeucedanin decrease. Conclusion: The experiment study the regulation of residues (SO2) and chemical contents with sulfur fumigation deepening to laid the foundation for the in-depth study.