Abstract: Urea was of great significance and it had wide application in actual production. But feeding urea directly also had some disadvantages. When feed was mixed unevenly or urea was excessively added, the release rate of ammonia in rumen was four times as its utilization rate by rumen microbe. In order to make full use of urea by ruminants and synchronization of utilizing ammonia and releasing ammonia of rumen microbe, a lot of studies were made. The research progresses on the application of urea-releasing technology in ruminants were summarized.