The relative dielectric constant ε′ and pyroelectric coefficient p of ferroelectric poly(vinylidene fluoride-trifluoroethylene) polymers P(VDF-TrFE) films grown on flexible substrates by Langmuir-Blodgett (LB) technique were measured, and room temperature figure of merit was obtained as 1.4 Pa^-1/2 at 1kHz. The result implies that LB P(VDF-TrFE) copolymer films are potential materials for pyroelectric detectors. This enhancement of figure of merit could be attributed to good crystallinity and highly planar ordered molecular chains in the LB films.