Objective: To analyze the epidemiological characteristics of infectious diseases among children and adolescents in Lanshan District, Linyi City, 2014-2023,so as to provide a scientific basis for prevention and control strategies in schools. Methods: The surveillance data were obtained from the China Information System for Disease Control and Prevention (CISDCP). Data on reported infectious disease cases and related demographic information among school children and kindergarteners in the study area from 2014 to 2023 were collected. Rate comparison was performed by using the χ 2 test. Trend analysis was conducted by using Joinpoint Regression Progrom, and the annual percent change (APC) and average annual percent change (AAPC) were calculated. Results: A total of 10 222 cases of infectious diseases among children and adolescents were reported from 2014 to 2023, with an average annual incidence rate of 273.32 per 100 000. The overall incidence trend remained stable from 2014 to 2023 (AAPC=12.33%, 95%CI=-2.63%-29.59%, P >0.05). Whereas a significant upward trend was observed from 2014 to 2019 (AAPC=37.08%, 95% CI =12.92%-66.41%, P <0.05), followed by a stable trend from 2019 to 2023 (AAPC=-0.31%, 95%CI=-39.70%-64.83%, P>0.05). Seasonal distribution exhibited dual peaks in summer and winter. The incidence rate in urban areas(707.29/100 000) was significantly higher than that in rural areas(257.50/100 000), and the incidence rate among kindergarteners (325.49/100 000) was higher than that among school children (257.07/100 000) (χ2=1 518.60, 116.36, both P<0.01). The reported infectious diseases among children and adolescents were predominantly respiratory and intestinal infectious diseases, with incidence rates of 156.13/100 000 and 108.51/100 000, respectively. Hand, foot, and mouth disease (HFMD) was the predominant infectious disease among kindergarteners, accounting for 47.51%. Influenza was the leading condition in the primary school group, accounting for 38.64%, and other infectious diarrheal diseases were most common in junior and senior high school group, accounting for 53.34%. The top six diseases by incidence rate were other infectious diarrheal diseases(65.22/100 000), influenza(63.24/100 000), varicella(46.34/100 000), HFMD(41.07/100 000), mumps(23.42/100 000), and scarlet fever(10.56/100 000). Among them, the incidence of other infectious diarrheal diseases rose significantly (AAPC=35.31%, 95% CI =14.32%-60.14%, P <0.01). The trend transitioned from a rapid escalation during 2014-2019 (APC=69.98%, 95% CI =17.58%-145.74%, P =0.01) to a stable phase during 2019-2023 (APC=1.74%, 95% CI =-15.61%- 22.66%, P >0.05). Conclusions In Lanshan, urban educational institutions should prioritize the prevention and control of infectious diseases, with particular emphasis on other infectious diarrheal diseases, influenza and varicella. Targeted interventions should be implemented in accordance with seasonal patterns and the specific characteristics of the school age populations.