To evaluate the relationship between platelet distribution width(PDW) and the extent of coronary artery disease and 2-year outcome in patients received percutaneous coronary artery intervention(PCI) because of stable coronary artery disease(SCAD). We consecutively enrolled 4 293 patients who received PCI because of SCAD in Fuwai Hospital from Jan 2013 to Dec 2013, patients were followed up for 2 years. Patients were divided into three groups according to tertiles values of PDW as follows: PDW≤11.4%(1 402 patients), 11.4%<PDW≤12.9%(1 441 patients) and PDW>12.9% (1 450 patients). Major adverse cardiovascular and cerebrovascular events (MACCE) were defined as the occurrence of death, myocardial infarction, target vessel revascularization, intra stent thrombosis and stroke during follow-up. Multivariable logistic regression was used to evaluate the relationship between PDW and the extent of CAD. Multivariable Cox regression was used to evaluate the relationship between PDW and prognosis of SCAD patients. PDW was associated with diabetes mellitus, body mass index, red cell distribution width, mean platelet volume (MPV), platelet counts and glycosylated haemoglobin (<0.05), but not associated with age, sex, estimated glomerular filtration rate (>0.05). PDW was not correlated with the extent of CAD(=0.990), SYNTAX score(=0.721), no-reflow phenomenon after PCI(=0.978). Multivariable logistic regression also showed no relationship between PDW and extent of CAD (=0.994, 95% 0.961-1.029, =0.73). PDW was found to be an independent risk factor of 2-year cardiac death (=1.242, 95% 1.031-1.497, =0.022), but was not an independent risk factor of all-cause death and MACCE. PDW is not related with the extent of coronary artery disease. PDW is an independent risk factor of 2-year cardiac death, but is not an independent risk factor of all-cause death and MACCE in this patient cohort.