The corpse, discovered near Pulvershaus in the commune of Erlen, has been identified as that of a 41-year-old Serbian man who lived in eastern Switzerland, the Swiss news agency SDA reported.
Thurgau police said an investigation was underway into the cause of death.
Police are seeking witnesses who may have noticed something unusual in the area in recent days or witnessed a fire.
The body was found around 100 metres from the Oberaach-Langrickenbach road.