The pressure dependence of excitation temperature (T(exc)) and electron density (n(e)) versus time was investigated to understand the characteristics of capillary Z-pinch argon (Ar) plasma. Measured profiles of several Ar lines were used to calculate T(e) and n(e). T(e) measured by Boltzmann plot method has a maximum of similar to 2.4 eV n(e) obtained from the Stark broadened line of Ar II wavelength 422.816 nm was similar to 10(17) cm(-3). Conditions in our system meet the assumption of local thermodynamic equilibrium (LTE), so using LTE to calculate T(e) and n(e) is valid in our system. (C) 2011 Elsevier B. V. All rights reserved.