Background: The aim of this study was to investigate the impact of body mass index (BMI) and body weight on the concentrations of ticagrelor and the ticagrelor metabolite, AR-C124910XX, as well as the platelet aggregation rate (PAR) in a Chinese Han population with unstable angina (UA). Specifically, it focused on these parameters following the administration of dual antiplatelet therapy (DAPT) comprising aspirin and ticagrelor. Methods: A total of 105 patients with UA were included in the study. Measurement of the platelet aggregation rate induced by adenosine diphosphate (PAR-ADP) was performed before, as well as 3 and 30 days after DAPT treatment. The plasma concentrations of ticagrelor and AR-C124910XX were detected at 3 and 30 days after DAPT treatment. We conducted correlation analyses to assess the effects of BMI and body weight on the concentrations of ticagrelor and AR-C124910XX, on PAR-ADP, and on the inhibition of platelet aggregation induced by adenosine diphosphate (IPA-ADP) at both 3 and 30 days after DAPT treatment. Results: The BMI and body weight were positively correlated with baseline PAR-ADP (r = 0.205, p = 0.007; r = 0.122, p = 0.022). The PAR-ADP at 3 and 30 days after DAPT treatment were significantly lower than at baseline (61.56% \pm 10.62%, 8.02% \pm 7.52%, 12.90% \pm 7.42%, p 0.001). There was a negative correlation between body weight and the concentrations of ticagrelor and AR-C124910XX at 3 days following DAPT treatment (r = –0.276, p 0.001; r = –0.337, p 0.001). Additionally, BMI showed a similar negative correlation with the concentrations of ticagrelor and AR-C124910XX (r = –0.173, p = 0.009; r = –0.207, p = 0.002). At 30 days after treatment, both body weight and BMI were negatively correlated with ticagrelor (r = –0.256, p 0.001; r = –0.162, p = 0.015) and its metabolite (r = –0.352, p 0.001; r = –0.202, p = 0.002). Body weight was positively correlated with PAR-ADP (r = 0.171, p = 0.010) and negatively correlated with IPA-ADP (r = –0.163, p = 0.015) at 30 days after treatment. Similarly, BMI was positively correlated with PAR-ADP (r = 0.217, p = 0.001) and negatively correlated with IPA-ADP (r = –0.211, p = 0.001) at the same time point. Conclusions: BMI and body weight are key factors influencing the pharmacokinetics and pharmacodynamics of ticagrelor in Chinese Han patients with UA following DAPT treatment that includes ticagrelor. Both BMI and body weight were positively correlated with PAR-ADP at baseline and 30 days after DAPT treatment. Clinical Trial Registration: ChiCTR2100044938, https://www.chictr.org.cn/.