Background and Objective: It has been well-established that long-term blood pressure variability (BPV) plays an important role in the progression of cerebrovascular vascular damage and the incidence of cardiovascular diseases. Knowledge about the association between long-term BPV and cognitive performance was scarce and ambiguous. This study aims to systemically examine the potential association between BPV and the trajectory of cognitive decline among Chinese adults, by using nationally representative population-based data from an 8-year prospective cohort. Methods: We used four waves (2011-2018) of the China Health and Retirement Longitudinal Study, including 5696 participants aged ≥45 years. BPV was measured using the within-individual standard deviation (SD) of mean systolic blood pressure (SBP) obtained from three waves visits, and the coefficient of variation (CV). The cognitive function was measured as the total score of episodic memory and mental status, with a higher cognition score indicating superior cognitive functions. Multivariable linear regression models were applied. Results: The mean value of SBP, mean SD of SBP and mean CV of SBP was 128.05 mm Hg and was 10.28 and 0.08, respectively. Both the SD (coefficient= -0.092, 95% CI= -0.144, -0.040) and CV of SBP variability (coefficient= -0.085, 95% CI= -0.137, -0.034) significantly decreased the risk of cognitive function. Subgroup analyses revealed significant relationships in both females and males. Conclusions: In middle-aged and older Chinese adults, higher long-term SBP variability could be an independent predictor of accelerated cognitive decline. Further high-quality studies are warranted to evaluate and confirm the benefit of BPV-lowering strategies for preventing cognitive impairment.