The microstructure of laser welds of sub-micron particulate-reinforced aluminum matrix composite Al_2O_(3p)/6061Al and the weldability of the material were studied. Experimental results indicated that because of the huge specific surface area of the reinforcement, the interfacial reaction between the matrix and the reinforcement was re- strained intenslvely at elevated temperature and pulsed laser beam. The main factor affecting the weldability of the com- posite was the reinforcement segregation in the weld resulting from the push of the liquid/solid interface during the soli- dification of the molten pool. The laser pulse frequency directly affected the reinforcement segregation and the reinfor- cement distribution in the weld, so that the weldability of the composite could be improved by increasing the laser pulse frequency. On the basis of this, a satisfactory welded joint of sub-micron paniculate-reinforced aluminum matrix com- posite Al_2O_(3p)/6061Al was obtained by using appopriate welding parameters. The microstructure of laser welds of sub-micron particulate-reinforced aluminum matrix composite Al 2 O 3 (3p) / 6061Al and the weldability of the material were studied. Experimental results indicated that because of the huge specific surface area of ​​the reinforcement, the interfacial reaction between the matrix and the reinforcement was re strained intenslvely at elevated temperature and pulsed laser beam. The main factor affecting the weldability of the com-posite was the reinforcement segregation in the weld resulting from the push of the liquid / solid interface during the solidification of the molten pool. The laser pulse frequency directly affected the reinforcement segregation and the reinfor- cement distribution in the weld, so that the weldability of the composite could be improved by increasing the laser pulse frequency. On the basis of this, a. joint of sub-micron paniculate-reinforced aluminum matrix com posite Al 2 O 3p 6061Al was obtained by using appopr iate welding parameters.