Superplastic boronizing (SPB) is a new surface hardening technique utilizing the ultra high plasticity phenomenon in metals in carrying out boronizing process. In boronizing, boron atoms are diffused into the metal substrate to form a hard boride layer. In this research, a new compression method for the SPB process was introduced. A clamp with an initial compressive load of about 1960 N was used. Thermo-mechanical treated duplex stainless steel (DSS) with fine grain microstructure which can show superplastic behavior at high temperatures was used as the superplastic material. SPB experiments were conducted at temperatures between 1123 and 1223 K for durations of 1 - 6 hours. The boronized specimens demonstrated thin, smooth and compact morphology of boride layer. The boride layer thickness was within ±10 0m - ±46.2 0m. On the boride layer, only the favorable single phase of Fe2B was detected. High value of surface hardness was observed in the range of ±847 HV - ±2914 HV. The overall results from the study show that the SPB process can significantly improve the surface properties of DSS.