A pivoting assembly with a positioning function includes a base and a casing assembled with the base. The base is provided with curved elastic arms and two fixing supports. Each fixing support has a pivotal hole. One surface of the casing is formed with a curved portion for allowing the curved elastic arm to abut against and two holes for allowing the fixing support to pass through. The other surface of the casing is formed with a protrusion pivotally connected to the pivotal hole. When the curved portion slides on the curved elastic arm, elastic abutment between the curved portion and the curved elastic arm makes the casing to be positioned by friction fit with respect to the base.