<p>Negative online comments have a significant impact on employee job crafting as the frequency of user interactions with companies increases. However, existing research on negative online comments mostly focuses on the impact on consumer behavior and ignores the positive impact on employee behavior. Based on cognitive appraisal theory, this paper constructs a dual-path model of competence frustration and challenge assessment, explores the negative and positive effect mechanisms of negative online comments on employee job crafting, and compares the differences — among employees with different working experience. By researching and analyzing 238 employees, the results of the study show that (1) negative online comments have a positive contribution to employee job crafting; (2) negative online comments foster employee job crafting via the positive behavioral route, enhancing their challenge assessment. Conversely, they fail to deter job crafting through the negative route, namely, increasing competence frustration. (3) the positive and negative effects of negative online comments on employee job crafting occur through different mechanisms at different working experience: at high working experience, negative online comments can further increase employee job crafting by increasing competence frustration and challenge assessment; at low working experience, negative online comments can not influence employee job crafting. The findings of this paper can help organizations and individuals objectively view the impact of negative online comments, optimize the application of negative online comments by companies and employees, and motivate employees to make proactive adjustments to their jobs.</p>