Ignition delay times of ethylcyclohexane with a fixed fuel concentration of 0.5% were measured behind reflected shock wave at pressures of 1.1-10.0 atm, equivalence ratios of 0.5-2.0, and temperatures between 1000 and 1700 K. The measured ignition delay times were compared to predictions by the mechanism JetSurF2.0, and fairly good agreements were presented under the test conditions. The ignition delay time of the fuel-rich mixture was suggested to overwhelm that of the fuel-lean mixture when tested at a low temperature and an elevated pressure. Analysis was conducted to kinetically interpret the effects of the pressure, temperature, equivalence ratio, and fuel concentration on the time histories of the OH radical and intermediate species of hydrocarbons. Results showed that the suppression of reaction H + O-2 (sic) OH + O by fuel-concerned radicals played an important role. Sensitivity analyses were carried out to provide insight into the controlling reactions on the ignition of ethylcyclohexane.