Abstract: Base pressure of a two-cell tile-shaped aerospike nozzle was measured under conditions of 10°,20°,30°,40° cell inclination and 0.0%,0.4%,1.0%,1.4%,2.0%,3.0% base bleed ratio.It was found that in the base region there exists open wake,close wake or open to close transition condition under different ambient pressure.Base aerodynamic behavior does not change with variations of cell inclination or base bleed ratio.Experimental performance change with altitude of two-cell linear aerospike nozzle truncated at 80%,40%,30% and 20% of the full plug length was obtained.The performance of the experimental aerospike nozzle and the pressure distribution along the plug were also computed.The predicted performance show good agreement with measured data.Based on experiments and numerical simulation,the effects of plug truncation and base aerodynamic behaviour on the performance of the aerospike nozzle are investigated.