The field emission of carbon nanotubes (CNTs) synthesized from different sources is investigated. Comparisons are made between graphite with Ni metal as catalyst and polycyclic aromatic hydrocarbon as precursor in arc discharge. Key parameters are also evaluated to obtain high quality and high yield CNT for application of field emission display. Cathode deposits are examined using SEM and HRTEM to determine microstructure. Raman spectroscopy is also used to study carbon structure. Electron field emission characteristic is measured with the diode method. Microstructural investigation provides evidence that both metal catalyst and precursor not only can be used to synthesize CNTs but also to enhance their production rate. From field emission measurement, the lowest onset field is about 1.0 V/mm and can be attributed to highly sharp tips and high density of CNTs. Based on microstructure characterization and field emission measurement, influence on field emission of CNT synthesized from different sources is discussed.