With the rapid development of technologies and the gradually increasing requirements of technology integration into teaching, teachers have been facing stress to keep pace with new technologies and to design pedagogical usage of technologies. Although prior studies have examined the creators and negative impacts of technostress, insights into the effective factors relieving teachers' technostress are rather limited. To facilitate teacher improvement with technology usage and help school administrators develop preventive stress management strategies, this study constructed a structural model among teachers' technostress, TPACK, computer self-efficacy, administration support, and collegial support, which were examined through a composite instrument adapted from previous studies. Data were collected from 366K-12 in-service teachers in China. After the exploratory factor analysis and confirmatory factor analysis, the results showed that the adapted instrument had adequate validity and reliability. Further, through structural equation modeling, the results indicated that administration support predicts teachers' computer self-efficacy, and collegial support predicts both teachers' TPACK and computer self-efficacy, which in turn negatively predict their technostress. The findings imply that primary and secondary school principals need to support teachers both administratively and through the creation of collegial professional learning communities to develop TPACK and computer efficacy to reduce teachers' technostress.