The effects of interlayer formation and thermal treatment on the field-emission properties of carbon nanotubes (CNTs) were investigated. The CNTs were prepared on tungsten (W) micro-tip substrates using the electrophoretic deposition (EPD) method. The interlayers, such as aluminum (Al) and hafnium (Hf) were coated on the W-tips prior to CNT deposition and after the deposition of CNTs all the species were thermally treated at $700^{circ}C$ for 30 min. The field-emission properties of CNTs were significantly improved by thermal treatment. The threshold electric field for igniting the electron emission was decreased and the emission current was increased. The Raman spectroscopy results indicated that this was attributed mainly to the enhancement of CNTs by thermal treatment. Also, the CNTs deposited on the interlayers showed the remarkably improved results in the long-term emission stability, especially when they were thermally treated. The X-ray photoelectron spectroscopy (XPS) measurement confirmed that this was resulted from the formation of the additional cohesive forces between the CNTs and the underlying interlayers.