The globe-like diamond microcrystalline aggregates were grown in the different growing time by microwave plasma chemical vapor deposition method on the ceramic substrate with a Ti metal layer. The carbon films were evaluated by Raman scattering spectroscopy, X-ray diffraction spectrum, and scanning electron microscopy. The field emission properties were tested by using a diode structure in a vacuum. The growth mechanism of the carbon films and field emission properties of the globe-like diamond microcrystalline aggregates were discussed. It was found that different carbon films prepared by deposition time greatly changes in morphology, and field emission results also change a lot. The decrease of field enhancement factor and the growth of conductive channel are the main reasons for deterioration of the field emission effect.