The invention relates to the technical field of fans, and particularly relates to a blade, an axial flow
fan blade and a fan. The blade comprises a pressure surface, a
suction surface, a blade root part, a blade top part, a
front edge part and a rear edge part, wherein a cylindrical surface where the blade root part is located is defined as a blade
root element surface, a cylindrical surface wherethe blade top part is located is defined as a blade top element surface, a cylindrical surface located between the blade
root element surface and the blade top element surface is a 1 / 2 element surface, and a cylindrical surface located between the blade top element surface and the 1 / 2 element surface is a 3 / 4 element surface; and the maximum distance between the
front edge part and the rear edgepart at the blade
root element surface is l1, the maximum distance between the
front edge part and the rear edge part at the 1 / 2 element surface is l2, the maximum distance between the front edge partand the rear edge part at the 3 / 4 element surface is l3, the maximum distance between the front edge part and the rear edge part at the blade top element surface is l4, and the values of 11, 12, 13 and 14 gradually increases. The outlet air speed can be effectively increased, the pneumatic performance of the blade is matched with a motor, and the
air volume of the fan made of the blade is guaranteed.