Abstract: An experimental investigation on the effect of tabs, which is fixed on the exit of a convergent nozzle, to thrust characteristics has been conducted at both subcritical and supercritical flow conditions. The variable parameters of tabs are block ratio, inclined angle and the number of tabs. The experimental results show that the tabs indeed cause thrust loss, and the thrust loss will increase with the block ratio of tabs. Within the test range of the experiments, the thrust loss is between 0.65%~1.35% per 1% tab block ratio, and especially about 0.8% per 1% at supercritical flow condition.