The purpose of this study was to assess the effectiveness of intervention with Yingyangbao (YYB) on hemoglobin (Hb) and anemia status among infants and young children (IYC) aged 6–23 months (mo) through a large-scale Nutrition Improvement Program for Children in Poor Areas (NIPCPA) in China from 2015 to 2020. Five rounds of cross-sectional surveys were conducted using a stratified and multi-stage probability proportional to size sampling of IYC in 2015, 2017, 2018, 2019 and 2020. Multivariable regression analyses were fitted to determine the effectiveness of the YYB intervention on Hb and anemia, respectively. A total of 36,325, 40,027, 43,831, 44,375 and 46,050 IYC aged 6–23 mo were included, and the prevalence of anemia was 29.7%, 26.9%, 24.1%, 21.2% and 18.1% in 2015, 2017, 2018, 2019 and 2020, respectively. Compared with the results in 2015, the Hb concentrations significantly improved and anemia prevalence significantly decreased among IYC in 2017, 2018, 2019, and 2020 (p< 0.001). Regression analysis showed that higher YYB consumption was significantly associated with the increment in Hb concentration and reduction in anemia stratified by age group (p< 0.001). The most significant increment in Hb concentration of 2.189 mg/L and the most significant reduction in odds of anemia were observed among IYC aged 12–17 mo who consumed 270 to 359 sachets of YYB (OR: 0.671; 95% CI: 0.627, 0.719;p< 0.001). This study suggests that YYB intervention is a successful public health strategy for reducing the risk of anemia among IYC when delivered through a large-scale NIPCPA in China. It is necessary to continue to advance the program and increase the adherence of YYB.