The extant literature has found highly mixed findings regarding the stress buffering effect of job resources. Drawing upon the resource allocation perspective, we argue that the buffering effect of job resources would emerge only when employees allocate the resources to wellbeing goal; when job resources are allocated to performance goal, they would no longer buffer the demand-strain relationship. We consider conscientiousness as a dispositional factor affecting resource allocation such that employees low in conscientiousness are more likely to allocate resources to wellbeing goal than to performance goal. In a sample of Chinese employees from high-tech industry (the mean age was 31.46, with 34.80% female), we found that job resources buffered the demand-strain relationship for employees low in conscientiousness. For those high in conscientiousness who tend to allocate more resources to performance goal, job resources did not affect the demand-strain relationship but strengthened the demand-performance relationship. This research makes a meaningful extension to the JD-R model and offers intuitive implications for organizations to manage job stress more effectively.