The nucleic acid adapters of tumor serum markers are oligonucleotide molecules with high specificity and high affinity with tumor serum markers obtained by in vitro screening with systematic evolution of ligands by exponential enrichment (SELEX). Researchers take the advantage of the nucleic acid adapter to explore new tumor serum markers that have more diagnostic value for tumor diagnosis. Recently, some achievements have been achieved in the research of liver cancer and stomach cancer. This paper has reviewed nucleic acid adapter and its research in the serum tumor marker screening, and discussed the value of the nucleic acid adapter of serum tumor markers in the diagnosis, as well as current problems existing in the research. This paper is very useful to help people better understand the screening of nucleic acid adapters of tumor serum markers, and to provide help in discovering new tumor serum markers.