The studies have been conducted on the effect of amorphous Ti-Ni-Ta-based surface alloy on the mechanical properties of TiNi alloy in microhardness, bending, and torsion tests. The synthesis of the Ti-Ni-Ta-based surface alloy (SA) was carried out by twofold alternation of operations of alloying film deposition (Ti60Ta40(at. %), ~ 100 nm thick) and liquid-phase mixing of the [film/substrate] system using a pulsed low-energy high-current electron-beam. Based on the obtained results, the following conclusions were drawn. In the samples with SA, the transition from the hardened (microhardness H ≈ 8 GPa) outer nanocrystalline layer (~100 nm thick, based on single β(Ti-Ta) phase) to the values of TiNi-initial (H ≈ 2 GPa) is provided by an amorphous sublayer (~750 nm thick). After quasi-static three-point bending tests, the magnitude of the accumulated strain ε is achieved at lower stresses σ (<60 MPa) in comparison with TiNi-initial. Heating of samples subjected to bending showed that the treatments accompanied by electron-beam modification during SA synthesis did not critically affect the shape memory effect of TiNi alloy. After quasi-static cyclic torsion tests, it was found that electron-beam synthesis leads to an increase in the martensite shear stress τМ by ~ 50 MPa, the stress hysteresis loop Δτ by ~ 30 MPa, and the material’s ability to accumulate and recover superelastic strain γSE greater by ~ 0.25 и ~ 0.16%, respectively, in comparison with TiNi-initial. The most important result is that after bending and torsion tests, amorphous SA has high adhesion strength to TiNi-substrate and do not peel off from them.