A new approach to model tomato's growth in view of the interaction between its physiological function and morphological structure was discussed. The finite state automaton called reference axis based on physiological age scale (i.e. structure model) was well applied to build tomato's topological structure and 3D geometrical structure including its leaf shape, leaf orientation and leaf insertion angle; while the tomato organ's size was simulated using the hydraulic model which was based on plant's transpiration law. We gave a detailed conceptual description of tomato growth axis and the spatial arrangement of its organs (internode, petiole, leaf truss, fruit and etc) according to reference axis model. With the correct computation of its topological structure, the organ's volume, surface, diameter and length were computed according to matter production and matter allocation mechanism at each developmental phase. The beta law was applied to simulate the sink variation. The parameters of the model were estimated from the data of given tomato (2001.5-7) using least square method. Good validation was obtained and the architecture of tomato at different stages was reproduced.