Health Secretary Alex Neil said more people than ever are coming to hospital as emergency admissions, blaming it on an ageing population.
Opposition parties said the decision reflects wider problems in the NHS.
The Scottish Government wants to reduce the number of A&E attendances but admits existing trends could lead to a 13.5% increase by 2020.
The investment, over three years, aims to change the way people are admitted to hospital, help them leave as soon as they are ready and improve links with other areas of healthcare.
Mr Neil said: "The majority of people who go to A&E don't need to be there and could get more appropriate treatment somewhere else, such as a minor injuries clinic. That's why we have developed this plan."
Health boards will increase the number of frontline staff and introduce more flexible hours, develop projects that offer options to be treated at home and offer separate facilities for minor injuries, the Government said.
Scottish Conservative health spokesman Jackson Carlaw said the Government has "spectacularly missed" its targets on A&E admissions.
Scottish Liberal Democrat health spokesman Jim Hume said: "The Health Secretary has been in denial and is late to the party in realising that Scotland's A&E units are in crisis."
A Scottish Government spokeswoman said: "Claims that A&E admissions targets have not been met are totally false – as there are no A&E admissions targets."