A PTC electric heating assembly, an electric heating device and an electric vehicle are provided. The PTC electric heating assembly (2) comprises two electrode plates (23) and a PTC heating module (20) disposed between the two electrode plates (23), and comprising an insulation fixing frame (22) and a plurality of PTC heating elements (21), the insulation fixing frame (22) defining a plurality of fixing units (220) and the PTC heating elements (21) being disposed into the fixing units (220) respectively.