The application of robot system to collaborate with human worker in production operation can greatly enhance manufacturing systems. In order to ensure successful implementation of such system, the effectiveness of the man-machine collaboration is the decisive factor. The main aim of this work is to model the collaboration between human and robot in cell production system by task analysis approach. In this work, the production operation is modeled into hierarchical task analysis (HTA) structure with the extension of collaboration modeling. The model is being validated by an actual assembly operation simulation. This work has enabled the study of collaboration modeling in order to design effective man-machine system in cell production.