BPDA (3,3',4,4'-biphenyl tetracarboxylic dianhydride)-MDA (p,p'-Methylene dianiline) polyimide was successfully synthesized. Critical surface tension T. and surface tension gamma(s) of BPDA-MDA polyimide film have been estimated by the contact angle method using our quantitative imaging system. The critical surface tensions gamma(e) were analyzed by a Zisman plot, a Young-Dupre-Good-Girifalco plot, and a log (1+cos 0) vs log gamma(L) plot. The Zisman plot is essentially a downwardly convex curve with polar and hydrogen bonding liquids having gamma(c) << gamma(L). The calculated values gamma(d)(S) (a dispersion component), gamma(p)(S) (a polar component), gamma(h)(S), (a hydrogen bonding component), and gamma(S) are 32.13, 4.93, 0.02, and 37.08 mN. m(-1), respectively.