Abstract: Compared with the traditional T/R modules, the 2.5D integrated silicon-based T/R modules implemented with TSV interposer are smaller, more integrated and possess better heat dissipation. Through-silicon-via (TSV) is one of the key structures. It is difficult to realize the finite element thermal simulation of complicated 2.5D integrated T/R modules, thus a solution which utilizes the equivalent thermal conductivity of TSV was employed to simplify the finite element analysis (finite element analysis, FEA) in this paper. The FEA of TSV with polymide liner (PI-TSV) was carried out and the structural parameters were changed to detect their effects on PI-TSV equivalent thermal conductivity. Finally, the empirical equation of PI-TSV equivalent thermal conductivity with respect to copper pillar diameter, insulation thickness and TSV pitch was presented.