Background: The spread of carbapenem-resistant Klebsiella pneumoniae (CRKP) that produces K. pneumoniae carbapenemase-2 has garnered significant attention due to its increasing prevalence. In China, the dissemination of K. pneumoniae carbapenemase-2-producing CRKP is predominantly linked to sequence type 11 (ST11), with capsular serotypes KL47 and KL64 being the primary capsular identified. Methods: A total of 64 CRKP-ST11 strains were collected from 2020 to 2023 and whole-genome sequencing was performed on all isolated ST11-CRKP strains. Antibiotic susceptibility was tested using the VITEK 2 system. Growth curve tests and in vitro competition experiments were used to assess the growth adaptability of different capsular type isolates. Moreover, the biofilm assessment and phagocytosis assays were performed to evaluate CRKP isolate virulence. Results: During the observed period, a notable subclonal shift was perceived within the prevailing ST11-CRKP clone, wherein the previously dominant KL64 and KL47 serotypes have been largely supplanted by the KL25 serotype since 2022. The ST11-KL25-CRKP strain significantly outgrew both ST11-KL64-CRKP and ST11-KL47-CRKP. Additionally, ST11-KL25-CRKP displayed a greater enhanced capacity to form biofilms than ST11-KL64-CRKP and ST11-KL47-CRKP. Furthermore, ST11-KL25-CRKP demonstrated enhanced resistance to phagocytosis than both of its counterparts. Conclusions: ST11-KL25-CRKP possesses a remarkable level of adaptability and has the potential to regionally replace ST11-KL64-CRKP as the predominant strain in the region. Additionally, this novel and high-risk ST11-KL25-CRKP strain may indicate stronger virulence.