The fuel atomization, fuel-air mixing and combustion performance can be directly affected by the structure of flow field in aero-engine combustor, therefore, the cold flow field and combustion flow field in a single-dome combustor are investigated by using Particle Image Velocimetry (PIV) in this paper. Influences of different inlet air flow rates on the area and the structure of re-circulation zone for the non-reacting flow fields are investigated experimentally separately. Moreover, influences of different inlet air flow rates and the fuel-air ratios on the structure of the combustion flow field are also studied experimentally. The experimental results show that the swirling flow at the cross section of the swirler's outlet is not complete due to the strong influence of the air jet from the primary hole on the bottom wall. The flow field structures for the cold flow and the combustion flow are similar, but the width of central recirculation zone for the combustion flow field is thinner compared with that of the cold flow field. With the increase of the fuel-air ratio, the width of central recirculation zone becomes narrower, the axial velocity becomes larger and the negative velocity of recirculation increases. At the same time, the fuel droplet velocity of the atomization cone can be captured in the dome of combustor during the measurement process of combustion flow field.