With the development of information and communication technologies (ICTs) and the wide use of intelligent instruments, web 2.0 has entered people’s daily life. On one hand, the wide use of ICTs help people make their role transitions between work and nonwork life more frequent and easier; on the other hand, frequent transitions between work and nonwork domains will come at a cost of work-nonwork conflict at the same time. Nowadays, due to the frequent use of communication tools and the special job characteristics of counselors (i.e., expanding work boundary, heavy workload, increasing role ambiguity), college counselor’s work-nonwork conflict is intensifying. Therefore, the purpose of this study is to explore ways to reduce college counselors’ work-nonwork conflict. In this study, we examined: (1) The effect of boundary segmentation preference on the work-nonwork conflict, under the proper control of some key confounding variables, (2) The moderation effects of the organization segmentation supplies and boundary?segmentation strategy on the relationship between boundary segmentation preference and work-nonwork conflict, based on the Boundary Theory. Participants were 312 college counselors (M age = 30.94, 155 males) from different colleges in China. They were requested to complete the boundary segmentation preference scale, the work-nonwork conflict scale, the organization segmentation supplies scale and the boundary?segmentation strategy scale on the spot. Cronbach’s alpha coefficients for the above measures were from 0.71 to 0.82, showing acceptable measurement reliabilities. The data was analyzed with the software SPSS 21.0 and Amos 21.0, and the main statistics methods were correlation analysis and multiple linear regression analysis. Having controlled some key confounding variables (i.e., age, marital status, spouses’ work status, tenure, whether the participant has children under the age of 18 and whether the participant is asked to keep their cellphone 24/7 available), the result showed: (1) Boundary segmentation preferences was positively related to work-nonwork conflict (r=.335, p＜0.001). (2) Organization segmentation supplies moderated the relationship between boundary segmentation preference and work-nonwork conflict. Specifically, the relationship between boundary segmentation preference and work-nonwork conflict became weaker with the increasing of segmentation supplies. Meanwhile, boundary?segmentation strategy moderated the relationship between boundary segmentation preference and work-nonwork conflict. The relationship between boundary segmentation preference and work-nonwork conflict became weaker with more boundary?segmentation strategies. Our findings provide strong theory support and specific guidance to reduce counselor’s work-nonwork conflict from the both aspects of organization and individual. On one hand, colleges should provide a split support policy to help counselors to maintain their work-nonwork boundary. On the other hand, counselors can use some boundary?management strategies (such as trying to complete the task before getting off work) to keep their work and life separated to a certain degree, so that they can better balance work-nonwork responsibilities.