Antiferromagnets have been attracting tremendous interest in the spintronics community due to their intrinsic appealing properties,such as zero stray field and ultrafast spin dynamics.Recently,the electrical manipulation of bulk properties of antiferromagnets has been widely studied,but exploring the use of antiferromagnetic (AFM) interfacial properties to investigate some key issues in spintronic devices is urgently desired.In this study,the magnetic and spin transport properties mediated by interlayer exchange coupling (IEC) are examined through spin-orbit torque (SOT)-induced tunability of interfacial spins in heavy-metal/like-synthetic antiferromagnet/antiferromagnet heterostructure devices.We found that the exchange bias and coercivity and the critical current density for SOT switching can be modulated by IEC,associating with the oscillation of SOT-induced interfacial spins reorientation at zero field,which can be well understood with the modified Ruderman-Kittel-Kasuya-Yosida model.Our finding opens a new route for understanding and using the AFM interfacial spins in spintronics.