The behavior of ddielectric 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-MDA polyimide film and analyzing the image quantitatively. All nonpolar liquids of alkane homologues easily spread on the the surface of BDPA-MDA polyimide. On the other hand, polar or hydrogen-bonding liquids form a certain angle on the surface of BPDA-MDA polyimide. Critical surface tension of BPDA-MDA polyimide estimated from Zisman plot is smaller than that calculated from the plot of 1+cosθ vs. 1/r L0.5plot or the plot of log (1+cosθ) vs. log r L plot.