Occupational therapy practice should be informed by the model of practice, with a focus on the needs of the clients and conducting activity analysis and occupational analysis on these needs. Intervention plans are developed in collaboration with clients/family members and they should be in control in decision making. In occupational therapy, the client is the active agent of activity, and the therapist serves as a helper or a facilitator. The design of therapeutic activities should not only consider restoring lost function and using residual functions but also pay attention to the impact of environmental factors on the client’s role and occupational performance. Occupational therapy helps the clients to return to family and society through improving their occupational performance via grading and adapting activities, providing information such as social resources, and implementing individualized interventions. This paper reviews the clinical reasoning and implementation of occupational therapy.