The change will apply to male and female Emiratis who hold a secondary school certificate or higher, UAE news agency WAM said.
Those that do not have a high school diploma will still serve for a minimum of two years.
Compulsory military service for Emirati men was first introduced in June 2014 in light of a growing regional instability.
The country has been an active part of a Saudi-led coalition in Yemen and the Western alliance operating in Syria and Iraq.
It also faces a land dispute with neighbour Iran over three contested islands in the Gulf