The behavior of dielectric material and manufacturing process of polyimide can be optimized by understanding relationship between surface chemistry and the wettability of polyimide. A general and useful method to predict the wettability of polyimide is to measure contact angle, which provides the information on surface tension, morphology and heterogeneity of the surface of polyimide. This research improves the existed repetitive and inexact method of measuring contact angle, and the improved measurement of contact angle can be reproducible and exact by capturing the image of the sessile drop on BPDA/ EDA polyimide film and analyzing the image quantitatively. All nonpolar liquids of alkane homologues easily spread on the the surface of BDPA/EDA polyimide. On the other hand, polar or hydrogen-bonding liquids form a certain angle on the surface of BPDA/EDA polyimide. Critical surface tension of BPDA/EDA polyimide estimated from Zisman plot is smaller than that calculated from the plot of 1+cosθ vs. 1/Υ 1^(o.5) plot or the plot of log (1 +cosθ) vs. logγ_(L) plot.