The design and implementation process of an automatic voice alarm system based on IMS are introduced. The process consists of hardware and software architecture. Compared with the schemes based on voice cards, the hardware system is based on a multimedia switch and supported by IMS; therefore, it has the advantages of high stability, concurrency, and strong expansibility. The software system is built under C/S and B/S structures: the C/S part with high manageability and configurability collects exceptions appeared in the meteorological communication and sends corresponding voice alarm, while the B/S part is responsible for the display, statistics and analysis of alarm information. The application results show that the automatic voice alarm system is stable and reliable.