The invention relates to a nanosecond pulse shaping and leading edge sharpening device. The device is of a coaxial cylinder structure, and comprises an oil tank shell, a GIS simulation tank body, a wavefront pulse shaping resistor, a guide rod, a sharpening switch and a sharpening switch gap adjusting unit and two supporting insulators, wherein the wavefront pulse shaping resistor, the guide rod, the sharpening switch and the sharpening switch gap adjusting unit are arranged along the axis direction of the GIS simulation tank body, the two supporting insulators are arranged along the direction perpendicular to the axis direction of the GIS simulation tank body, two ends of the sharpening switch are fixed on the two supporting insulators respectively, a first end of the sharpening switch is connected with one end of the guide rod, and the other end of the guide rod is connected with one end of the wavefront pulse shaping resistor; the other end of the wavefront pulse shaping resistor is connected with the output end of an impulse voltage generator; a second end of the sharpening switch is connected with one end of the sharpening switch gap adjusting unit; the other end of the sharpening switch gap adjusting unit is arranged outside the shell of the GIS simulation tank body, and the guide rod and the fuel tank shell form an intermediate energy storage oil line. The device disclosed by the invention can solve a problem that the nanosecond pulse waveform does not reach a set standard because of existence of loop inductance.