Stimulatory effects of aluminium (Al) on the growth of tea plants (Camellia sinensis L.) and nutrio-physiological roles of Al in tea plants were examined. The findings obtained were as follows: (1) Tea plants preferred primarily acidic conditions; (2) When Al was supplied to tea plants in the presence of P, growth was greatly stimulated, probably by improvement of the absorption and the utilization of P. The optimum level of Al for tea plants increased with increasing P supply; (3) Application of Al improved the absorption and the utilization of K. In addition, Al remarkably alleviated excessive toxicity of Mg; (4) Application of Al was similar to but more favorable than the effect of B on the growth of tea roots; and (5) The growth of excised tea roots in shaking liquid culture in vitro was stimulated by supplying Al and P together, but was not affected by Al and P supplied separately.