The effect of laser shock processing on the microstructure, hardness and residual stress of an austenitic steel 1Cr18Ni9Ti and a Ni-base superalloy GH30 is studied as a functions of laser shock processing variables. Results show that high density of dislocations and deformation twins are produced in the laser shock processed zone of both the austenitic steel 1Cr18Ni9Ti and the nickel-based superalloy GH30. Extensive strain-induced martensite plates are also observed in the laser shock processed zone of the austenitic steel surface. The hardness and compressive stress of the laser shock processed surface are significantly increased for both of the test materials.