The metal oxide semiconductor (MOS) core shell heterostructure nanofibers (NFs) have been successfully synthesized via an environmentally friendly coaxial electrospinning approach. To demonstrate the potential applications of the as prepared samples, sensors based on MOS core shell heterostructure NFs have been fabricated, and their gas sensing properties were investigated. Results show that the sensors exhibit an advanced gas sensing property to trimethylamine (TMA) including the outstanding selectivity and rapid response/recovery processes in comparison with the sensors based on single MOS NFs. These phenomena are closely associated with the electron flow caused by the work function difference between MOS of the core and the shell. The approach proposed in this study may contribute to the realization of more sensitive MOS core shell heterostructure sensors.