Abstract: An integrative D-dot monitor is designed to measure high voltage pulse in transmission line. The monitor which consists of base, airproof BNC connector, probe shell, insulation, probe and connecting rod is located on the outshell of transmission line. Monitor assemblies are coaxially connected by thread, resulting in compaction of configuration and integrality in dismounting or mounting. An airproof BNC connector and a seal packing ring of oxygen-free copper are used to get good sealing performance and veracity, meanwhile their low elasticity leads to high accuracy of measurement. Low ground capacitance of monitor is designed to get good high-frequency response. Simulation by OrCAD/Pspice is taken, with good signal-to-noise ratio and rising time. Results of simulation on electrostatic field by CST show that the monitor is safe to measure 1 MV high voltage. Results of calibration and experiment show that the integrative D-dot monitor can response to signals with rise time of several tens of nanoseconds, which could fulfill our diagnostic requirement.