An ultrasonic surgical blade, wherein the blade has a curved shape, and both sides of the blade are provided with cutting surfaces, one surface is a concave surface and the other surface is a convex surface. The thickness of the blade is gradually thinned along a cutting direction from a proximal end to a distal end. The concave surface length is set as L1, the radius of curvature R1； the length of the convex surface L2, the radius of curvature R2； the angle of the bending of the center line of the blade is α； the diameter of the proximal end of the blade is D； the thickness of the most distal end surface of the blade is T. The relationship among them is: L1=L2+L2/1.5*(D−；T)*SIN(α) (1), R1=R2+2T (2). The range of each size is adjustable within 10%. An ultrasonic wave guide and an ultrasonic scalpel using this blade have fewer potential resonant frequencies, so the thermal damage to the tissue is small, and the performance is more stable.
