Objective: To observe the predictive value of serial platelet function testing (PFT) on outcome in patients undergoing complex percutaneous coronary intervention (PCI). Methods: Six hundred and two consecutive patients undergoing complex PCI in Anzhen hospital were enrolled during October 2011 to June 2012.Adenosine diphosphate(ADP)-induced platelet aggregation was measured by light transmission aggregometry on the first, sixth and twelfth month after PCI and the mean value was calculated.The cut-off value of high on-treatment platelet reactivity (HTPR) was defined as 40%.The primary endpoint was major adverse cardiovascular and cerebral event (MACCE). Clinical outcomes were analyzed by the Kaplan-Meier method and differences were compared using the log-rank test.Multivariate analyses by Cox proportion hazards regression were applied to identify variables independently associated with the adverse outcomes. Results: Five hundred and eighty-five patients (HTPR, n=285; non-HTPR, n=280) finished the follow-up ((28.47±7.45) months). A total of 33 cases of MACCE were observed during the follow-up, among which 29 cases(8.42%) were in HTPR group and 9 cases (3.21%) in the non-HTPR group.Kaplan-Meier analysis suggested that HTPR was associated with an increased incidence of MACCE (log-rank test, P=0.01). The Cox multivariate analysis indicated that HTPR was an independent risk factor of MACCE (HR=2.69, 95%CI 1.23-5.85, P=0.01) in patients undergoing complex PCI.Incidence of MACCE was similar between HTRP patients receiving standard dual antiplatelet therapy (DAPT) or prolonged DAPT (>12 months). Conclusion Serial PFT could predict the long-term prognosis of patients underwent complex PCI.