Repeat coronary revascularizations (RCR) are common in patients underwent percutaneous coronary intervention.There is no available prediction model for RCR at present.The association between paraoxonas-1 (PON1) and the development,progression,and prognosis of coronary artery disease is under hot research.The rela-tionship of serum PON1 activity level and RCR has not been reported.This research aimed to detect the difference of serum PON1 activity levels between RCR and single coronary revascularization(SCR) ,hence to illuminate the value of PON1 in predicting RCR.Methods Serum PON1 activity levels of 200 patients who had achieved complete revascu-larizations in first percutaneous coronary intervention (PCI) were determined by colorimetric method.All patients re-ceived one-year follow-up.Coronary angiographies were performed at 6th month.Patients who need more revasculariza-tion procedure during follow-up were enrolled in RCR group; those who did not need more revascularization procedure were enrolled in SCR group.One hundred patients with normal coronary angiography during the same period were setup as non-coronary heart disease control group (NCC) .Results Sixty two patients were enrolled in RCR group (28 with in-stent restenosis,34 with lesion progression in other coronary segments) .Serum PON1 activity levels in RCR group, SCR group and NCC group were 109.2 ± 98.6 μkat/L,132.8 ± 79.4 μkat/L and 156.4 ± 82.8 μkat/L,respective-ly.Statistic differences were found among three groups (P < 0.05) .Conclusions Serum PON1 activity levels are lower in patients who need repeat coronary revascularizations than in patients need single percutaneous coronary inter-vention or without coronary heart disease.A lower serum PON1 activity level is closely associated to repeat coronary re-vascularization. Repeat coronary revascularizations (RCR) are common in patients underwent percutaneous coronary intervention. There is no available prediction model for RCR at present. The association between paraoxonas-1 (PON1) and the development, progression, and prognosis of coronary artery disease is under hot research. the rela-tionship of serum PON1 activity level and RCR has not been reported. this research aimed to detect the difference of serum PON1 activity levels between RCR and single coronary revascularization (SCR), hence to illuminate the value of PON1 in predictive RCR . Methods Serum PON1 activity levels of 200 patients who had achieved complete revascu-larizations in first percutaneous coronary intervention (PCI) were determined by colorimetric method. All patients re-ceived one-year follow-up. Coronary angiographies were performed at 6th month. Patients who need more revasculariza- tion procedure during follow-up were enrolled in RCR group; those who did not need more revascularization procedur E were enrolled in the SCR group. One hundred patients with normal coronary angiography during the same period were setup as non-coronary heart disease control group (NCC). Results Sixty two patients were enrolled in RCR group (28 with in-stent restenosis, 34 with lesion progression in other coronary segments) .Serum PON1 activity levels in RCR group, SCR group and NCC group were 109.2 ± 98.6 μkat / L, 132.8 ± 79.4 μkat / L and 156.4 ± 82.8 μkat / L, respective-ly. Statistic differences were found among three groups (P <0.05) .Conclusions Serum PON1 activity levels are lower in patients who need repeat coronary revascularizations than in patients need single percutaneous coronary inter -vention or not coronary heart disease. to repeat coronary re-vascularization.