Each policy is in need of knowledge. But both the research community and the government-user agencies appear to agree on the conclusion that social research is underused or misused. In the real world, experiential knowledge usually has had a greater impact on public policy-making than research-based knowledge. Under such circumstances, how to apply ordinary knowledge and research-based knowledge successfully to the policy making process became the primary concern in the field of knowledge utilization. This essay is organized into the following sections: conceptions of knowledge and the relation between research-based and experiential knowledge; types of knowledge utilization; theoretical perspectives on knowledge utilization process; responsibility for knowledge underutilization, and strategies for promoting knowledge utilization.