Tumor immunotherapy is a novel strategy for cancers, which has great significance and application prospects in clinical treatment. It mainly includes adoptive cell therapy, tumor vaccines and monoclonal antibody therapy. Antibodies are widely used in tumor immunotherapy, but their price is too high, the quality is easily influenced by different batches and have immunogenicity. Aptamers, also known as “chemical antibodies”, are short single-stranded oligonucleotides which bind to their targets with high specificity and affinity. Aptamers which have low immunogenicity, are synthesized at low cost and quality stability. Based on these advantages, aptamers have been developed for tumor immunotherapy in recent years which mainly includes two aspects. One is to select immune-related aptamers, and the other is to expand the application of aptamers that have been reported to tumor immunotherapy. Using immune checkpoints, co-stimulatory receptors or cytokines as targets, the aptamers can be obtained through screening. However, it is uncertain whether the aptamer has the biological function of regulating the anti-tumor immune response. Therefore, the process of screening should be improved by adding appropriate screening pressure to obtain functional aptamers that can regulate antitumor immune response. There are many aptamers which have been reported, but rarely have been investigated for further research and application. So we can further develop these aptamers for tumor immunotherapy. For example, aptamers can be coupled with siRNA or nanomaterials to indirectly regulate tumor immune processes. The modification of membrane of immune cells with aptamers confers the immune cells targeted tumor-killing effects. Aptamers play an important role in tumor immunotherapy in a variety of ways, and have great potential to be developed for clinical treatment. We need to improve the aptamer screening process to obtain aptamers that have powerful biological functions quickly and maximize the use of the aptamers that have been obtained.