The invention relates to five N-methyl-3,5-bis(3-(2-phenol methylene amino)) 4-piperidone Schiff base derivatives used for suppressing tumor and a preparing method thereof, and belongs to the technical field of antitumor drugs and a preparing method thereof. The preparing method includes the steps that N-methyl piperidone and m-nitrobenzaldehyde are subjected to a Claisen-Schmidt condensation reaction to obtain an intermediate, the intermediate compound is reduced with a reducing agent to obtain a reduction product, and finally the final finished products A-E are obtained through an aldol condensation reaction. By using the N-methyl-3,5-bis(3-(2-phenol methylene amino)) 4-piperidone Schiff base derivatives A-E, genotoxicity of antitumor drugs used at present can be avoided, the antitumor activity is high, and the target ability is high. The preparing method is simple, reaction conditions are mild, and the synthetic yield is large, which is beneficial for widely popularizing the derivatives in the antitumor field.