A curved and toothed cutting blade for a trimmer comprising a base body having at least a connecting member for mounting onto a trimmer and a longitudinal cutting edge on one side which is symmetrically concave downward and has teeth, wherein the curve of the cutting edge is in the form of a segment of the interior of a circular arc of a lens with the two interior angles of any teeth not having different degrees of angle and the dent in between any two teeth being not perpendicular to the base pitch of the tips of the two teeth and slanted towards the center point of the curve of the cutting edge; and a grinding wheel for manufacturing the cutting blade, wherein the cutting blade is manufactured by a grinding wheel which is in the form of a lens with the two endpoints truncated with diameter being the largest in the middle and gradually decreasing towards the two ends and the surface of which has grooves of sizes and shapes which correspond to the sizes and shapes of the teeth of the cutting blade. The manufacturing process is simple and of low cost.