In order to investigate the functions of DCL genes in Dimocarpus longan, we isolated gene sequences of DlDCL1, DlDCL2, DlDCL3 and DlDCL4 from D. longan genome data. Analysis of cisacting elements and regulation of miRNA were performed on the DlDCLs family members. Expression of DlDCLs were analyzed in embryogenic callus (EC) under abiotic stress and exogenous hormone treatment in D. longan. The results showed that: (1) the promoters of D. longan DCL genes not only included the cisacting elements of TATA and CAAT box, but also had a large number of light response elements, hormone response elements, stress response elements, tissue specific regulatory elements and other ciselements for plant growth and development. These results suggested that the transcriptional activity of the promoters of D. longan DCL gene might be induced by the signals of light, phytohormones and abiotic stresses. (2) The miRNAs were screened for their effect in regulating D. longan DCL genes, and the results showed that DlDCL1 was regulated by miR162 and miR1024, while DlDCL4 was regulated by miR390 and miR396. (3) The expression of DlDCLs was analyzed by realtime quantitative PCR. It was found that after GA₃, ABA and ETH treatments, DlDCLs gene were downregulated. However, they were dramatically upregulated under high concentration of ETH treatment. (4) DlDCL2, DlDCL3 and DlDCL4 were upregulated when they were treated with high concentration of sucrose (6%), in the exception of DlDCL1, which was significantly increased at 0.1% sucrose concentration. During heat treatment, DlDCL1 was significantly upregulated at 34 ℃, whiles the DlDCL3 gradually decreased with rising temperature. The expression level of DlDCL2 and DlDCL4 exhibited slight variations. NaCl treatment induced the response of DlDCLs at different time intervals, however, inhibited the expression of DlDCLs at 1 h. The expression patterns of D. longan DCL genes response to hormones and abiotic stresses suggested that DlDCLs gene were not of a simple one to one correspondence but rather a complex response mechanism.