BACKGROUND: Phubbing is a commonly seen phenomenon that has emerged in recent years among groups of college students, posing a rising challenge to educators. We conduct research in which the reciprocal relationship between problematic social media use and phubbing is explored and analysed quantitatively, aiming to discover reliable theoretical support to work out an appropriate intervention on students' phubbing for students' mental health concerns. METHODS: Using the problematic social media use scale and the phubbing scale, 328 college students from four universities in Shandong Province were enrolled in a two-stage longitudinal follow-up study for 20 months from December 2019 to August 2021. A cross-lagged model was constructed to explore the reciprocal relationship between problematic social media use and phubbing. The results of correlation analysis showed that problematic social media use was positively correlated with phubbing at both time points (r = 0.51, 0.53, P < 0.01). RESULTS: The results of cross-lagged regression analysis showed that the predictive effect of pretest problematic social media use on posttest problematic social media use was statistically significant (β = 0.24, P < 0.01). There was statistical significance in the prediction effect of pretest phubbing on posttest phubbing (β = 0.16, P < 0.05). Pretest problematic social media use had statistical significance in predicting posttest phubbing (β = 0.22, P < 0.01), and there was no statistical significance in the prediction of pretest phubbing on posttest problematic social media (β = 0.16, P < 0.05). CONCLUSION: The problematic social media use of college students is closely related to phubbing, and problematic social media use can predict phubbing.