The contents of sucrose,glucose,fructose,total sugar and the activities of sucrose-metabolizing enzymes in the Chinese olive fruits of ‘Makeng 22’and ‘Tantou 23’were compared.Results showed that:(1)Sucrose rapid accumulation period was the key to sucrose accumulation difference between ‘Makeng22’ and ‘Tantou23’,and it also affected soluble sugar content of fruit when fruit was ripe.(The ratio of hexose to sucrose was 0.668 in the ripe ‘Makeng22’ fruit.The ratio of hexose to sucrose was 0.904 in the ripe ‘Tantou23’ fruit.(2)In sucrose rapid accumulation period,AI activity of‘Makeng22’ was lower than that of ‘Tantou23’,which created a chance for sucrose rapid accumulation.And NI activity of ‘Makeng22’ was higher than that of ‘Tantou23’,which strengthened the fruit sink.SPS activity changes of ‘Makeng22’ and ‘Tantou23’ were similar,so SPS was not the key to the sucrose accumulation.The growth of ‘Makeng22’ fruit SuSy(synthesis direction)activity was higher than that of ‘Tantou23’ in after full bloom 144 d-186 d,so SuSy(synthesis direction)was the key to the sucrose accumulation.(3)Sucr-ose rapidly accumulating relied mainly on SuSy synthesis direction activity changes to promote the increase of sucrose content in ‘Makeng22’ fruit.Sucrose rapidly accumulating relied mainly on SuSy cleavage direction activity changes to promote the speed of sucrose into fruit in ‘Tantou23’ fruit.