The realization of mid-infrared thermal radiation based on metamaterials insensitive to angle and polarization plays an important role in various thermal photonic applications. However, the challenges include the following: most previously designed thermal emitters usually contain metal components with unsatisfied physicochemical stability, accompanied with complex manufacturing technology. The present study proposes a mid-infrared thermal emitter at 3–6 μm wavelength range based on Fibonacci quasi-periodic structure, and a flat one-dimensional structure based on Fibonacci geometry resorting to ITO is designed. The proposed thermal emitter is, theoretically and experimentally, proven to possess good angular and polarization-independent selective thermal emission performance in a relatively wide infrared wavelength range. Furthermore, the good optical and high-temperature thermal stability of the designed thermal emitter is verified in the present experimental research. The thermal emitters proposed have advantages in polarization-independence without scale restraint and low cost but with wide vision. In summary, the present study provides a new tactics for obtaining non-metal spectral selective thermal emitters in a relatively wide wavelength range and thermal photonic applications under harsh conditions.