Based on grounded theory, this study systematically investigates the antecedents of work meaningfulness and meaninglessness and their relations using a large-sample open-ended questionnaire survey. It constructs a theoretical framework of “work meaningfulness-meaninglessness” and explores it across different generations. Findings reveal that the antecedents of work meaningfulness are contribution, self-actualization, recognition, relationship, context, leaders’ behaviors and job content in order of prevalence. The antecedents of work meaninglessness are context, leaders’ behaviors, job content, non-self-actualization, others’ negative perceptions, relationship and lack of contribution in order of prevalence. Work meaningfulness and meaninglessness are not mutually exclusive, but rather a relation as “work meaningfulness-no work meaningfulness” and “work meaninglessness-no work meaninglessness”, and they are influenced by factors of meaningfulness stimulation and meaninglessness stimulation respectively. There is no significant generational difference in the antecedents of work meaningfulness. However, the antecedents of work meaninglessness differ, with the pre-reform generation highlighting the impact of leaders’ behaviors, the reform generation emphasizing organizational context, and the post-reform generation stressing the roles of organizational context and job characteristics.