The present invention discloses a 
nucleic acid aptamer, wherein the sequence of the 
nucleic acid aptamer comprises 
a DNA segment represented by any one sequence selected from a sequence 1, a sequence 2 and a sequence 3. The 
nucleic acid aptamer can further be various similar sequences with 
high homology or a derivative obtained from the sequence of the present invention. The invention further discloses a nucleic acid aptamer 
screening method, which comprises: synthesizing a random single-stranded 
DNA library and primers, carrying out SELEX screening, carrying out PCR amplification of 
library, preparing 
a DNA single strand library, and finally carrying out repeated screening, negative screening and multi-round screening to obtain the nucleic acid aptamer. The nucleic acid aptamer and the derivative thereof can be used in recognition of the 
prostate cancer cell strain PC-3 or preparation of kits, molecular probes and targeted mediums for 
prostate cancer detection, and can further be used in design and preparation of 
prostate cancer treatment drugs. Compared with the 
protein antibody, the nucleic acid aptamer of the present invention has advantages of high affinity, high specificity, no 
immunogenicity, capability of being chemically synthesized, small molecular weight, stability, easy storage, easy labeling and the like.