Experiments are carried out to investigate the effects of dome structure on the combustion performance of a trapped vortex combustor. The effects are directly explored in terms of combustion efficiency, ignition and lean blowout limits with three different dome structures. The experimental results indicate that the fairing-tube configuration exhibits excellent advantages in lean blowout limits and the outer-cavity ignition performance, whereas the fairing-plate configuration performs rather poorly. Interestingly, the fairing-plate configuration shows prominent superiority in the ignition performance of the inner-cavity. Additionally, the basic configuration performs moderately both in ignition and lean blowout limits. For the combustion efficiency, the fairing plate configuration achieves the highest combustion efficiency when only cavity is fueled. Both expected and unexpected results are found when cavity and mainstream are fueled simultaneously. As anticipated, higher combustion efficiency are achieved by the basic configuration and fairing-plate configuration at low fuel/air ratio conditions. However, the highest combustion efficiency is obtained by the fairing-tube configuration at high fuel/air ratio conditions. Numerical simulations of non-reacting flows are then conducted to explain the experimental results. The great discrepancies in combustion characteristics may mainly attribute to the significant differences of the flow patterns both in cavity and mainstream.