Pulmonary hemodynamic changes in 63 chronic obstructive pulmonary disease (COPD) were studied with right heart catheter and impedance pulmonary rheogram (IPR) both at rest and during exercise. The two regression equations for estimating exercise PAPM with rest and exercise IPR parameters were established as follows: PAPM (kPa) = -1.40-0.88lnHs + 8.30B-F + 5.78Q-B/B-Y. PAPM (kPa) = 6.46-5.04Hs/square root of R-R + 4.35Q-B/B-Y-19.34Q-C.6 patients with normal rest PAPM were found to have PAPM increased during exercise and 4 patients with Cor Pulmonale had normal PAPM both at rest and at exercise. PCWP in all patients with and without Cor Pulmonale was normal. We also found that SV, SVI reduced significantly at exercise when compared with these at rest. With the patient's condition aggravating. SV, SVI decreased while RVSWI and dp/dt max of right ventricular systolic pressure increased.