Silver azide (AgN3) primary explosive was successfully prepared by in-situ reaction with hydrazoic acid (HN3) using micron-scale silver(I) oxide (Ag2O) as the precursor. Ag2O particles have been synthesized through a facile chemical precipitation method. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the prepared materials. The effects of reaction time on the morphology and phase composition of silver azide were evaluated. Silver azide can be synthesized by in-situ reaction for 12 h. Increasing the azide reaction time is beneficial to the generation of silver azide but has no obvious influence on the morphology. The prepared silver azide micro-charge can be successfully initiated by Ni-Cr bridge wire and present favourable explosion performance.