Abstract: Objective: Changes in β-adrenoceptors （β-AR） in heart and lung during asphyxiated cardiac arrest were investigated. Methods: The β-AR of the membrane fraction of the heart or lung were analyzed by binding assay with the use of ³H-Di-hydroalprenolol（³H-DHA） as radioligand. The rats were divided into control（A）、sham（B）、asphyxiated 10 min（C）、20min（D） and 30min（E）group. Results: The β-AR number in hesrt and lung were （34.51±3.25）fmol/mg pr. and （289.46±19.96） fmol/mg pr. in group C,respectively. The β-AR numbers in heart and lung In group D and E were （40.96 ±2.91） and （64.44±3.20） fmol/mg pr.、（426.33±12.08） and （455.67±28.77）fmol/mg pr. respectively. （P＜0.01,compared with group C）. The affinite （K D） of β-AR in heart and lung in the asphyxiated groups were not altered. Conclusion: The β-AR number in rat heart and lung increased （upregulation）after cardiac arrest as the cardiac arrest time prolonged.