Mr Pfleger joins from ABB's Robotics division where he headed up business unit systems. He has also had roles ar Alstom Energy and Alstom Power.
Chief executive Samir Brikho said: "Mr Pfleger is hugely experienced in the energy, power and process industries, having worked on large, difficult, yet successful turnkey projects in a number of geographies over the last 15 years.
"I have worked with him briefly in the past and am delighted he is now joining Amec. I am confident he will provide a strong lead, enabling us to achieve our strategy in the power and process markets."
Mr Pfleger starts his new role on December 1 and will also join Amec's management committee.