With an aim to develop an ignition model and obtain the key factors influencing the ignition limits in aero-engine combustor, testing and theoretical investigations were conducted based on the ignition process inside a single dome gas turbine combustor. The characteristic curve of ignition process was obtained, and a method to optimize the ignition performance was also proposed. An ignition model to predict the ignition limits was developed based on the concept of recovery time, and the accuracy of the prediction model was validated. It is found that the significant improvement in ignition performance can be obtained by decreasing the atmozation performance of nozzle. A very satisfactory agreement is demonstrated between the predictions based on the prediction model and the actual measured values. The maximum error of the prediction model is less than 20%, which is qualified to meet the requirements of the combustor design.