A stibarsen (Derived from Latin stibium antimony and arsenic) or allemontite, is a natural form of arsenic antimonide (SbAs) with the same layered structure as arsenic and antimony. Thus, exploring the two-dimensional (2D) SbAs nanosheets is of great importance to gain insights into the properties of V-V compounds at the atomic scale. Here, we propose a new class of two-dimensional V-V honeycomb binary compounds, SbAs monolayers, which can be tuned from semiconductor to topological insulator. By ab initio density functional theory, both α -SbAs and γ -SbAs display significant direct bandgap, while others are indirect semiconductors. Interestingly, in atomically thin β -SbAs polymorph, spin-orbital coupling is significant, which reduces its band gap by 200 meV. Especially, under biaxial tensile strain, the gap of β -SbAs can be closed and reopened with concomitant change of band shapes, which is reminiscent of band inversion known in many topologically insulators. In addition, we find that Z 2 topological invariant is 1 for β -SbAs under the tensile strain of 12%, and the nontrivial topological feature of β -SbAs is also confirmed by the gapless edge states which cross linearly at Γ point. These ultrathin V-V Group semiconductors with outstanding properties are highly favorable for applications in novel optoelectronic and quantum spin hall devices.