This paper presents the simulation investigations on the enhancement technology regarding the contact pressure sensitivity of the Fibre Bragg Grating (FBG) sensor. The FBG was embedded in a patch made of polymer material in order to increase its pressure sensitivity. The polymer coating converted the transverse pressure to longitudinal strain, which could further perturb the FBG. The strain distribution was not uniform in the FBG patched layer and therefore the Bragg wavelength deviated from the theoretical result. The difference caused by the non-uniform strain distribution was investigated. The effect of temperature was eliminated by the use of a grating multiplexing technique. FBG was composed of multiple sub-gratings with different strain distributions. A transfer matrix of sub-gratings was calculated and integrated to obtain the final reflected spectrum of the FBG. With the patch layer coating, pressure sensitivity of a silica FBG with λB = 1550 nm was increased to 5 nm/MPa, which was 1000 times higher than the original FBG without a patch.