Abstract: Carbon nanotube（CNTs） film was directly grown on Ni/Au substrate by pyrolysis of iron Phthalocyanine（FePc）. The intense pulsed emission characteristics of such CNTs film were measured in single pulse with a diode structure. It is found that the smaller the A-K（Anode-Kathode） gap is, the emission current of the cold cathode is larger, and the value of turn-on electric field is samller. Under the same pulsed electric field（~12.1 V/μm）,the peak current of CNTs film is 312 A（equivalent current density 15.9 A/cm²） and 747.2 A（equivalent current density 38. OA/cm²）, corresponding the values of turn-on electric field be 4.3 V/μm and 4.0 V/μm. when the A-K gap distances are 14 cm and 12.8 cm, respectively.