Objective: To investigate the incidence trend of tuberculosis in Haidong City, Qinghai Province from 2006 to 2020, and the effects of age, period, and cohort on tuberculosis incidence, so as to provide the basis for enhancing the prevention and control for tuberculosis. Methods: Data of tuberculosis cases in Haidong City from 2006 to 2020 were collected from the Chinese Disease Prevention and Control Information System. Incidence rates were calculated and standardized using data from the Sixth National Population Census in 2010. The trends in incidence of tuberculosis were analyzed by annual percent change (APC). Effects of age, period and cohort on the incidence of tuberculosis were analyzed by an age-period-cohort model. Results: The crude incidence rates of tuberculosis in Haidong City from 2006 to 2020 ranged from 37.69/105 to 100.93/105, and the standardized incidence rates ranged from 42.85/105 to 115.24/105. The standardized incidence rates from 2006 to 2015 showed a decreasing trend (APC=-7.148%, P<0.05), while there was no significant trend observed from 2015 to 2020 (all P>0.05). The age-period-cohort model analysis showed that the highest incidence risk of tuberculosis in Haidong City from 2006 to 2020 was observed in the age group of 20-<25 years (RR=2.973, 95%CI: 2.353-3.756), followed by the age group of 80-<85 years (RR=2.785, 95%CI: 2.206-3.516). The incidence risk of tuberculosis was higher in the period from 2016 to 2020 (RR=1.253, 95%CI: 1.203-1.306) compared to the period from 2011 to 2015 (RR=0.796, 95%CI: 0.770-0.823). Tuberculosis incidence risk was the highest in the birth cohort from 1936 to 1940 (RR=3.050, 95%CI: 2.356-3.949), and then gradually decreased over time thereafter. Conclusions The incidence of tuberculosis in Haidong City showed a decreasing trend from 2006 to 2015, while there was no significant trend observed from 2015 to 2020. The incidence risk of tuberculosis was higher in the age groups of 20-<25 years and 80-<85 years, and the risk decreased for those born in more recent years.