Abstract The traditional Chinese timber structure with columns directly placed on the foundation has the characteristics of the rocking structure. Determining initial modes of response under horizontal acceleration is essential to the analysis of subsequent response for rocking structures. This paper extends the initial mode criteria of the rigid free-standing column to the plane motion of the traditional Chinese timber frame to obtain the analytical distribution of the timber frame. A finite element model of the typical traditional Chinese timber frame was established and then a parameter analysis was performed; the simulation results were consistent with the analytical distribution. The results have identified four types of initial modes: rest, slide, pure-rock, and slide-rock. For the traditional Chinese timber frame with column aspect ratio 0.14, only two initial modes (rest and pure-rock), which were mutually exclusive, appeared in the initial response. The initial response study presented here provides a theoretical route to the dynamic response of traditional Chinese timber structures for earthquake hazard mitigation and structural health monitoring.