In the Internet era, the rapid development of mobile communication tools has made it common for employees to use electronic communication to handle work affairs during off-hours. In this context, a new way of work connectivity behavior has begun to attract the attention of scholars. Work Connectivity Behavior is based on the innovation of contemporary information technology, which means that individuals use mobile devices to complete work or deal with work-related affairs during off-hours. However, previous studies have shown that there is a paradox in the effect of job connectivity. Activists believe that work connectivity behavior promotes job resource flow among different fields and improves employees’ work output; negatives believe that work connectivity behavior makes employees' family life encroached and has a negative impact on individual family relations. Integrating the above two views, this paper puts forward the double-edged sword effect of job connectivity behavior, and reveals the moderating effect of employee's polytonicity on the double-edged sword effect. Based on the job demand-resource model, work connectivity behavior can not only promote the work goals progress and improve the job performance of employees (job resource process), but also increase the workload of employees and trigger work-family conflict (job demand process). Moreover, polytonicity respectively moderate the impact of work connectivity behavior on employees' job performance and work-family conflict. Specifically, when employees with high polytonicity, work connectivity behavior is more likely to bring work resources and promote the work goals progress; however, when employees with low polytonicity, work connectivity behavior is more likely to increase work demand and increase the workload. Based on 258 three-point leader-employee supervisor-employee dyads, Mplus7.0 was used to conduct path analysis to test the research hypothesis. The results show that: (1) Work connectivity behavior has a positive impact on employee performance through work goal progress. (2) Work connectivity behavior leads to work-family conflict through workload. (3) Polytonicity moderate the relationship between work connectivity behavior and job goal progress, and the indirect relationship between work connectivity behavior and job performance through work goal progress. For individuals with high polytonicity, work connectivity behavior has a more significant positive impact on work goal progress and job performance. (4) Polytonicity moderate the relationship between work connectivity behavior and workload, and the indirect relationship between work connectivity behavior and work-family conflict through workload. For individuals with low polytonicity, the negative impact of work connectivity behavior on workload and work-family conflict is more significant. By revealing the double-edged sword effect of work connectivity behavior and the regulatory role of multiple time orientations, the academia and industry have deepened their understanding of the advantages and disadvantages of work connectivity behavior, and provided enlightenment for how to play the positive role of work connectivity behavior and reduce the negative role. For employees with low polytonicity, when executing work connectivity behavior to deal with work affairs in off-hours, they should reasonably control the number of work, properly perform family duties, and reduce or avoid work-family conflicts. In addition, organizations can enhance employees' polytonicity through training, cultural construction and other activities, so as to give full play to the positive effect of work connectivity behavior.