A new liquid source chemical vapor deposition process is introduced for preparing (Ba, Sr)TiO3 (BST) thin films from Ba(DPM)(2)(tetraglyme), Sr(DPM)(2)(tetraglyme), and Ti(DPM)(2)(i-OC3H7)(2) (DPM = dipivaloylmethanato) dissolved in butylacetate, The film deposition mechanism as well as the BST film growth rate are determined by studying the film formation and the associated chemical reaction kinetics as a function of temperature and gas now rates. It is demonstrated that in the formation of BST films, the three precursors, TiO2, BaTiO3, and SrTiO3, react and produce deposits or intermediates independently. The deposition rate of BST Rims is the summation of the respective growth rates of the BaO, SrO, and TiO2 films. The gas-phase decomposition reactions of the precursors, rather than their surface reactions on the substrate, dominate the BST film growth rate. The kinetics of the three overall chemical reactions to produce the oxide films of Ba, Sr, and Ti are determined by comparing the experimental film deposition rates and the numerical results. The suggested chemical reaction kinetics and the traction rate constants are expected to be important in the design of metallorganic chemical vapor deposition reactors for BST films.