Abstract: 【Objective】 To study the molecular mechanism of CaCl₂ alleviating salt stress in sour jujube seedlings.This study provides a reference for the study of the molecular mechanism of CaCl₂ to alleviate the salt damage of sour jujube (Zizyphus jujuba Mill.) through transcriptome sequencing analysis.【Method】In this study, the seedlings of sour jujube were treated with 150 mmol/L NaCl and 150 mmol /L NaCl + 10 mmol /L CaCl₂ for 6 hours respectively. The transcriptome sequencing and assembly of leaves and roots of sour jujube seedlings were carried out by high-throughput sequencing technique,and all Unigenes obtained were annotated in GO and KEGG databases. 【Result】The results showed that compared with the control group, under exogenous CaCl₂ treatment, 7,365 and 1,247 differential expressed genes were up-regulated and down-regulated in the leaves of sour jujube seedlings, 762 and 4,861 in the roots, respectively.【Conclusion】GO database comparison showed that there were 43 GO conditions enriched in leaves and 42 GO conditions enriched in roots of sour jujube seedlings. and most of the differentially expressed genes were enriched in the cell membranes of the leaves and roots. KEGG database comparison revealed that the differentially expressed genes were mainly involved in plant-pathogen interaction, MAPK signaling pathway-plant, Plant hormone signal transduction, phenylpropanoid biosynthesis, pentose and glucuronate interconversions, etc.