Abstract: In this paper, sheet metal stress-strain relations in uniaxial and biaxial tension were theoretially and experimentally investigated. The interrelation of two n values respectively derived from uniaxial and biaxial tension test and their suitness for predicting sheet metal forming limits were given. The stress-strain relations of studied materials in uniaxial and biaxial tension were also used to analyse and calculate sheet metal deep-drawing process and its forming parameters. The results showed that the stress-strain relation under uniaxial tension stress state is more suitable to analyse sheet metal deep-drawing process.