Abstract: By employing the tree-growth model, the relationship between the cell size of tree ring and climate for Huashan pine from the Qinling Mts is studied. The cell sizes of early wood, late wood have been measured and modeled using the climate data for 37 years. The modeled cell sizes of Huashan pine and its evolution coincide greatly with the observed one. Response of the measured cell size chronologies to climate indicate that the growth of Huashan pine is mainly effected by the precipitation of current growing season from April to July and of the prior year. The effect of temperature on cell size is shown only in April with a positive correlation.