Laser shock peening (LSP) is a surface treatment process for increasing the strength and reliability of metal components. Traditionally applied to aircraft parts, the technology also shows great potential for automotive and medical applications. The present study investigates the effect of multiple laser peening with and without coating on the hardness of aluminum alloy. The Vickers micro-hardness test is used to study the hardness of the alloy in different layer of the sample with different wavelengths and laser intensity. It has been initially found that metal hardness can be significantly increased with the increase of laser intensity and also with the increase of number of laser shots irradiated per unit area.