For the past two decades, organic electronics has been a hot topic due to the ability of commercial low-cost and large-area flexible electronics. Organic semiconductors (OSs) are significantly used in electronics reliant on organic substances. For the primary problem of the chemical materials, the new OS construction has improved accomplishment in organic thin-film transistors (OTFTs). The main reason for the successful attainment of high-performance OTFTs is to control the interface between the substrate and dielectric layer. Though OTFT is considered for better enhancement, there still exists a major issue that is to increase the mobility and resistance to temperature, humidity and chemicals on polymer gate insulators. Thus, to overcome these issues, the designed model is based on the OTFT using Tri-layer dielectric polymers such as SiO2, PEI-EP (Polyetherimide – Epoxy polymer) and POM-H (polyoxymethylene homopolymer) with pentacene semiconductor to evaluate the electrical performance. The electrical characteristics are validated by comparing tri-layer dielectric OTFT with single and Bi-layer dielectric OTFT. Electrical characteristics such as Threshold voltage (VT), On/Off ratio, and carrier mobility (μ) of the tri-layer dielectric OTFT are validated, and resultant values for those parameters are 0.51v, 10-3-100 and 0.51 ± 0.31cm2 .Thus, the deigned tri-layer pentacene OTFT model performs better electrical characteristics compared to the single and bi-layer OTFT.