In the process of gene expression, time delays are unavoidable due primarily to the slow process of transcription, translation and translocation processes. It is observed that gene regulatory system may lose its stability even for very small delay. Motivated by the regulation of gene expression proposed in Shimoni et al. [Molecular Systems Biology, 2007], in this paper, a gene regulatory network mediated by small non-coding RNAs with both transcriptional and translational time delays is formulated. The nonlinear dynamic behaviors such as stability, bifurcations and oscillations are studied. It is shown that both transcriptional and translational time delays can induce gene expression in Escherichia coli to be oscillatory even when its deterministic counterpart exhibits no oscillations. Moreover, the obtained results are in consistence with experimental observations found in the biological literatures [Elowitz MB et al.: Nature, 2000, 403, pp.335–338; Lennart Hilbert et al.: Mol. BioSyst, 2011, 7, pp.2599–2607], which indicates that when time delays are significant, both transcription and translation should be taken into account in the regulation of gene expression.