In this study, batch thermal conduction heating (TCH) experiments were performed in a TCH simulation device with trichloroethylene (TCE) as a typical contaminant to investigate the effects of temperature field distribution, soil water content, and heterogeneity on TCE transport in homogeneous and heterogeneous layers consisting of silt, medium sand, and coarse sand. The results showed that the temperature differences between the upper and lower layers of the heterogeneous fine and coarse-grained layers increased, while those in the heterogeneous coarse and fine-grained layers remained relatively stable, with the increase of water content. In addition, the TCE migration radius in homogeneous coarse sand exceeded that in heterogeneous systems by 18-23% under the same conditions. Stratigraphic heterogeneity dominated TCE distribution patterns, with pronounced gas accumulation (up to 37% higher vapor density) beneath fine-grained layers, compared to heterogeneous layers. In addition, the phenomenon of lateral migration of pollutant gases in heterogeneous soil layers is severe, providing a relevant basis for the application of gas extraction technology utilising differences in soil pore pressure. These findings would provide critical insights for optimizing in-situ thermal remediation in layered subsurface environments.