Smartphone technologies have played a crucial role in the fight against the COVID-19 pandemic; however, the increased use of smartphones during the pandemic period may expose the general public to a higher risk of problematic smartphone use (PSU). This study aimed to estimate the prevalence of PSU among Chinese community adults and adopted a social-cognitive theory and social axiom framework to evaluate the effects of beliefs on PSU. A Chinese adult sample ( = 616) was obtained through probability sampling via a telephone survey from Macao, China and included 591 smartphone users' data (39.4% men) for formal analysis. The prevalence of PSU was 43.3% in the overall sample, with 41.9% in women, and 45.5% in men. Two types of beliefs derived from the social-cognitive theory, pandemic-related self-efficacy and government efficacy, both showed significant and negative correlations with PSU ( = -0.13 and -0.10, < 0.05). As for the two beliefs from the social axiom framework, reward for application was negatively correlated with PSU ( = -0.10, < 0.05), whereas social cynicism was positively associated with PSU ( = 0.25, < 0.001). Among those four beliefs, social cynicism exerted the most substantial effect on PSU when controlling for demographics. Our findings enriched the understanding of PSU during the pandemic and provided empirical direction regarding cognition-based intervention strategies for reducing PSU.