This　paper　proposes　a　novel　three-lobe　rotor　tooth　profile　with　the　cross　section　of　a　combination　of　eccentric　arcs　and　cycloidal　curves　for　the　Roots　blower.　Based　on　the　geometric　modelling　of　this　new　tooth　profile,　a　helical　tooth　profile　and　a　comparative　study　between　the　spur　and　the　helical　three　lobes　have　been　presented.　The　study　reveals　the　advantages　of　the　new　helical　tooth　profile　design　which　creates　greater　air　flow　and　reduces　the　peak　of　the　blower　pressure.　The　tooth　profile　machining　and　testing　are　provided　at　the　end　of　this　paper.