Nanopores, due to their advantages of being modifiable, controllability and sensitivity, have made a splash in recent years in the fields of biomolecular sequencing, small molecule detection, salt differential power generation, and biomimetic ion channels. In these applications, the role of chemical or biological modification is indispensable. Compared with small molecules, the modification of polymers is more difficult and the methods are more diverse. Choosing an appropriate modification method directly determines the success or failure of a research project; therefore, it is necessary to summarize polymer modification methods toward nanopores. In addition, it is also important to provide clear and convincing evidence that the nanopore modification is successful, the corresponding characterization methods are also indispensable. Therefore, this review will summarize the methods of polymer modification of nanopores and efficient characterization methods. We hope that this review will provide some reference value for like-minded researchers.