Trifoliate orange which was the rootstock of Gannan ‘Newhall’ navel orange intended to promote as test material and the method of nutrient solution culture was used to study the effects of boron deficiency on the seedling growth of orange rootstock and the changes among different elements.The results showed that boron deficiency inhibited the growth of plants,decreased dry matter accumulation and significantly reduced the contents of boron in leaves.The new leaves reduced by 39.5%-49.1% and the old leaves reduced by 33.3%-39.4%.Potassium content in tips of trifoliate orange seedling under boron deficiency significantly reduced by 18% more than that under the normal boron level.Calcium content in tips of trifoliate orange seedling and in new leaves under boron deficiency decreased 12%-49% and 11%-13%.Magnesium content had a tendency to increase under boron deficiency.The content of nitrate and soluble protein significantly reduced under boron deficiency.