The low ratio of sugars and organic acids is one of the major reasons for poor taste in kernelapricot sarcocarp. In this study, to understand the expression patterns of genes which may be associated with sugar and organic acids synthesis and to indentify the molecular regulation pattern and mechanism of the low ratio of sugars and organic acids, we used RNAseq technique to obtain the transcriptomes and expression profiles of three developing stages (30, 60 and 90 days after flowering) about kernelapricot sarcocarp of ‘Shanku 2 hao’ to provide a basis for the study of the metabolic and conversion mechanism of sugars and organic acids in kernelapricot sarcocarp.The results showed that: (1) 28 989 differently expressed unigenes were obtained during the three developing stages.According to the unigene annotation, 5 enzymes encoded by 19 unigenes related to sugar biosynthesis and metabolism and 15 enzymes encoded by 54 unigenes involved in organic acids biosynthesis and metabolism were obtained; (2) Among the differently expressed unigenes, 9 and 27 unigenes of them which related to sugar and organic acid biosynthesis and metabolism were differently expressed in the three developing stages,respectively; (3) Most of the unigenes encoding the sucrosephosphate synthase and sucrose synthase which related to the sugar accumulation were downregulated, but the fructokinase and hexokinase that involved in sugar catabolism were upregulated; (4) The unigenes encoding malate dehydrogenase which associated with accumulation of malic acid was the main components of organic acids in kernelapricot sarcocarp were mainly upregulated. However, the malic enzyme catalyzed the breakdown of malic acid was downregulated. It can be sure that the accumulation of sugars was restrained, but the organic acids were synthesized and accumulated in large quantities during the developments of kernelapricot sarcocarp. This may be one of the main internal factors that contribute to the low ratio of sugars and organic acids and the poor taste of kernelapricot sarcocarp.