The objective of this study is to investigate the engineering properties and design the slope stability of granite at the Doi Ngom mine in Phrae, Thailand. The study involves data collection and sampling of rocks from the mine, including three types: fresh granite, weathered granite, and granite soil. samples were subjected to testing at the rock mechanics laboratory to determine parameters such as natural water content, dry density, porosity, specific gravity, point load strength, and uniaxial compression strength. Subsequently, the slope stability of the mine is designed to obtain a factor of safety by using limit equilibrium analysis; Bishop’s simplified and Janbu’s simplified methods and the design utilizes strength parameters obtained from laboratory testing. The results aim to design a slope pit wall with a safety factor of more than 1.5, and the height and berm width of the bench remained the same, but the bench face angle and overall slope were reduced.