Background <p>The rapid increase in the elderly population in China has led to the dual challenges of cognitive decline and physical functional decline. Grip strength, a key indicator of physical function, may have a bidirectional relationship with cognitive function. However, research on the association and bidirectional dynamics between the two, especially in the elderly population in China, remains limited.</p> Objective <p>This study aims to investigate the longitudinal bidirectional associations between grip strength, global cognitive function, mental intactness, and episodic memory, and to examine the trajectory of these indicators over time.</p> Methods <p>This study is based on the China Health and Retirement Longitudinal Study (CHARLS), which included 4,442 eligible individuals aged 60 and above, spanning from 2011 to 2015. Grip strength was measured using a standardized dynamometer, while global cognitive function was assessed through mental intactness and episodic memory metrics. Cross-lagged panel models and linear mixed-effects models were employed to assess the bidirectional associations between grip strength, global cognitive function, mental intactness, and episodic memory, controlling for various confounding factors, including sociodemographic characteristics.</p> Results <p>During the 4-year follow-up, individuals with greater baseline grip strength exhibited higher scores in global cognitive function (<i>β</i> = 0.055, <i>p</i> = 0.001), mental intactness (<i>β</i> = 0.048, <i>p</i> = 0.006), and episodic memory (<i>β</i> = 0.049, <i>p</i> = 0.011) at follow-up. Baseline global cognitive function, mental intactness (<i>β</i> = 0.024, <i>p</i> = 0.019), and episodic memory (<i>β</i> = 0.040, <i>p</i> &lt; 0.001) also significantly predicted grip strength at follow-up (<i>β</i> = 0.041, <i>p</i> &lt; 0.001). A comparison of the cross-lagged coefficients revealed that the effect of baseline grip strength on episodic memory was significantly greater than the reverse pathway (Δ<i>χ</i>2 = 5.089, <i>p</i> = 0.024). The linear mixed-effects model analysis further confirmed this result, showing that lower baseline cognitive function and weaker grip strength independently predicted the accelerated decline of both over time.</p> Conclusion <p>This study provides new evidence for the longitudinal bidirectional relationship between grip strength, global cognitive function, mental intactness, and episodic memory in the Chinese elderly population, emphasizing the importance of improving both grip strength and cognitive function. Notably, baseline grip strength has a stronger effect on subsequent episodic memory than the reverse pathway, which carries important public health implications. Maintaining optimal grip strength may be an effective intervention strategy to delay age-related cognitive decline.</p>