A gas-filled recoil separator, SHANS (Spectrometer for Heavy Atom and Nuclear Structure), constructed at the Institute of Modern Physics in Lanzhou is reported. With the QDQQ magnetic configuration, where D and Q denote the dipole and quadrupole magnets respectively, the apparatus is used to study the heavy nuclei produced in the heavy-ion-induced fusion reactions. The helium gas is filled in the field region of the separator at a pressure of about 1 mbar. The maximum magnetic rigidity of the dipole magnet is 2.9 Tm. With the commissioning of the device, the performance of the separator in several fusion evaporation reactions is investigated.