SnSe, a layered material with intrinsic low thermal conductivity, is reported to have excellent thermoelectric properties. SnSe ₂has a similar structure to SnSe, but the SnSe ₂has a low electrical transport, resulting in a poor thermoelectric performance, and the intrinsic SnSe ₂has a maximum ZTvalue of only ~ 0.09 at 773 K. In this work, SnSe _1.98Br _0.02- y%Cu ( y= 0, 0.50, 0.75, 1.0) bulk materials are synthesized by the melting method combined with spark plasma sintering (SPS) based on the carrier concentration improved through Br doping. In the SnSe ₂materials with van der Waals chemical bonding between layers, the synergistic effects of intercalating Cu on the thermoelectric properties are investigated. On the one hand, the extra Cu not only provides additional electrons but also can be embedded stably in the van der Waals gap and form an intercalated structure, which is beneficial to the charge transfer in or out of the layers, and thus synergistically improving the carrier concentration and carrier mobility. On the other hand, owing to the dynamic Cu doping, the increase of carrier concentration compensates for the decrease of carrier mobility caused by carrier-carrier scattering, which maintains the high electrical transport properties at high temperature. The present results show that at room temperature, the power factors along the parallel and perpendicular to the SPS (// Pand ⊥ P) sintering directions increase from ~0.65 and ~0.98 µW·cm ^–1·K ^–2for intrinsic SnSe ₂to ~10 and ~19 μW·cm ^–1·K ^–2for SnSe _1.98Br _0.02-0.75%Cu samples, respectively. Finally, at 773 K, the maximum ZTvalue of ~0.8 is achieved along the ⊥ Pdirection. This study proves that the SnSe ₂greatly promises to become an excellent thermoelectric material.