Abstract: Flow characteristics in LEC-III combustor liner of a 9E gas turbine were numerically simulated under premix mode, so as to study the velocity field, temperature field and species field in the liner. Results show that the circulation zone generated by combined action of secondary fuel nozzle and centerbody swirler can stabilize the flame in combustor liner, and the centerbody swirler is able to control the combustion range, which is very important to the flame stability in secondary combustion zone. The NO emission concentration reduces gradually with the rise of purging air flow rate, and the simulated results of NO emission are close to actual measurements, with similar variation trends observed simultaneously.