The selection of non-hazardous solvent systems is an important factor that can significantly influence fiber formation during polymer electrospinning. In this paper, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/polyethylene oxide (PEO) has been electrospun using different solvent systems to investigate the influence of different solution properties on nanofiber morphology and diameter, the thermal and mechanical properties, as well as the degradation kinetics of the electrospun fibers. The morphology, thermal and mechanical properties of PHBV/PEO electrospun fibers were characterized using scanning electron microscopy (SEM), thermogravimetric analysis (TG) and differential scanning calorimetry (DSC), and a universal testing machine, respectively. The results showed that the binary-solvent system (dichloromethane/ethanol DCM/EtOH) gave the finest defect-free fibers, and exhibited the best thermal and mechanical properties of all the single solvents (chloroform (CHL), dichloromethane (DCM)). Therefore, the effect of DCM/EtOH in different ratios on PHBV/PEO electrospun fibers was studied in detail. In brief, the DCM/EtOH solvent system was considered to be the best candidate for PHBV/PEO for electrospinning.