A hedge trimmer, comprising: a motor; a housing for containing or fixing the motor; a main handle being formed with a main gripping portion for a user to grip; a guiding bar extending along a longitudinal axis and protruding out of the housing; and a couple of cutting blades coupled with the guiding bar movably and driven by the motor to do a reciprocating motion along the longitudinal axis, wherein each cutting blade comprises: a base body extending along the longitudinal axis, several cutting portions connected with the base body and extending in a direction of a lateral axis which is substantially perpendicular to the longitudinal axis, the cutting portions are spaced from each other in a direction of the longitudinal axis, wherein the base body is formed with several coupling holes for coupling the cutting blades with the guiding bar movably, the coupling holes go through the base body in a direction of a vertical axis which is substantially perpendicular to the longitudinal axis and the lateral axis, wherein each cutting portion comprises a bottom surface and a cutting surface, the cutting surface is intersected obliquely with the bottom surface, and the bottom surface and the cutting surface form a cutting edge, characterized in that in the direction of the vertical axis, the cutting edge comprises a first section close to the bottom surface and a second section far from the bottom surface, and the first section and the second section form the entire cutting surface, and wherein a surface hardness of the first section is greater than or equal to 750HV1 and less than or equal to 800HV1, and the surface hardness of the second section is greater than or equal to 310HV1 and less than or equal to 360HV1, and wherein in the direction of the vertical axis, a ratio between a size of the first section and a size of the cutting portions is greater than or equal to 0.03 and less than or equal to 0.1. a motor; a housing for containing or fixing the motor; a main handle being formed with a main gripping portion for a user to grip; a guiding bar extending along a longitudinal axis and protruding out of the housing; and a couple of cutting blades coupled with the guiding bar movably and driven by the motor to do a reciprocating motion along the longitudinal axis, wherein each cutting blade comprises: a base body extending along the longitudinal axis, several cutting portions connected with the base body and extending in a direction of a lateral axis which is substantially perpendicular to the longitudinal axis, the cutting portions are spaced from each other in a direction of the longitudinal axis, wherein the base body is formed with several coupling holes for coupling the cutting blades with the guiding bar movably, the coupling holes go through the base body in a direction of a vertical axis which is substantially perpendicular to the longitudinal axis and the lateral axis, wherein each cutting portion comprises a bottom surface and a cutting surface, the cutting surface is intersected obliquely with the bottom surface, and the bottom surface and the cutting surface form a cutting edge, characterized in that in the direction of the vertical axis, the cutting edge comprises a first section close to the bottom surface and a second section far from the bottom surface, and the first section and the second section form the entire cutting surface, and wherein a surface hardness of the first section is greater than or equal to 750HV1 and less than or equal to 800HV1, and the surface hardness of the second section is greater than or equal to 310HV1 and less than or equal to 360HV1, and wherein in the direction of the vertical axis, a ratio between a size of the first section and a size of the cutting portions is greater than or equal to 0.03 and less than or equal to 0.1. a base body extending along the longitudinal axis, several cutting portions connected with the base body and extending in a direction of a lateral axis which is substantially perpendicular to the longitudinal axis, the cutting portions are spaced from each other in a direction of the longitudinal axis, wherein the base body is formed with several coupling holes for coupling the cutting blades with the guiding bar movably, the coupling holes go through the base body in a direction of a vertical axis which is substantially perpendicular to the longitudinal axis and the lateral axis, wherein each cutting portion comprises a bottom surface and a cutting surface, the cutting surface is intersected obliquely with the bottom surface, and the bottom surface and the cutting surface form a cutting edge, characterized in that in the direction of the vertical axis, the cutting edge comprises a first section close to the bottom surface and a second section far from the bottom surface, and the first section and the second section form the entire cutting surface, and wherein a surface hardness of the first section is greater than or equal to 750HV1 and less than or equal to 800HV1, and the surface hardness of the second section is greater than or equal to 310HV1 and less than or equal to 360HV1, and wherein in the direction of the vertical axis, a ratio between a size of the first section and a size of the cutting portions is greater than or equal to 0.03 and less than or equal to 0.1.