The invention discloses a carbon nano tube catalyst loaded with a Fe complex. According to the carbon nano tube catalyst, a 1,3-butanedione derivative serves as a raw material, and is subjected to condensation together with arylamine under the heating condition by using the catalyst so as to generate a 3-(arylamino)but-2-en-1-one derivative. The invention further discloses a method. According to the method, the raw materials are cheap and easy to obtain. The prepared catalyst has the advantages of being reusable, economical and environmentally friendly, the yield of a target product is high, the reaction can be expanded to the gram-scale, and in addition, the product can be used as a drug synthesis precursor.