Obtaining a low Schottky barrier remains a challenge in edge-contact heterojunction. We investigate the electronic properties of SnSSe with eight metals (Ag, Al, Au, Cu, Nb, Ni, Ta, and Ti). It is found that a low n-type Schottky barrier forms in all edge-contact heterojunctions and the different heterojunctions exist in different Schottky barrier heights (SBH) with 0.187–0.287 eV. Owing to the anisotropy of SnSSe, the different electronic properties of the heterojunctions are exhibited with SnSSe in different transport directions. Furthermore, we use the external electric field to modulate the Schottky barrier of all heterojunctions and found a shift in the contact type of heterojunction. A weak Fermi level pinning effect makes most heterojunctions achieve Ohmic contact under the electric field, which indicates better electronic transport. The results provide a way to design edge-contact electronic devices with tunable Schottky contact by the electric field. [ABSTRACT FROM AUTHOR]