Taking the optimizing plant ‘Libo3’ and ‘Libo11’ Prunus mume which was native to Guizhou Province as materials, using the method of ultra performance liquid chromatograph (UPLC), we measured the changes of organic acid contents and relative metabolic enzyme activities during the development of Prunus mume fruit. The results showed that:（1）citric acid and malic acid of ‘Libo3’ and ‘Libo11’ mainly accumulated in the late period of fruit development, after anthesis the accumulation of citric acid reached the maximum at 140 d, the amount of total acid in the fruit also accordingly reached the maximum value. （2）The accumulation of citric acid was related to the activity of citrate synthase (CS), the content of citric acid of ‘Libo11’ was higher than that of ‘Libo3’ since for its CS activity was higher at the ripening stage.（3）The content of malic acid exhibited positive correlation with the activities of PEPC and NADMDH, while the NADPME activity exhibited negative correlation. The difference in malic acid accumulation is mainly caused by the coordination change of PEPC, NADMDH and NADPME activities. After anthesis 45 to 100 d , the activities of PEPC and NADMDH increased rapidly, while the NADPME activity was relatively low, promoting the massive accumulation of mailc acid. After anthesis 120 to 140 d, PEPC and NADMDH activities of ‘Libo3’ was significantly higher than the activities of ‘Libo11’, while NADPME activity of ‘Libo11’ was lower. As a result, the content of malic acid of ‘Libo11’ is higher when mature. The late period of fruit development is a critical period for the accumulation of malic acid and citric acid. The accumulation of total organic acids was regulated by multiple enzymes. The difference in malic acid accumulation is mainly caused by the coordination change of PEPC, NADMDH and NADPME activities, while the difference in the accumulation of citric acid is mainly affected by the change of CS activity.