Based on TSV technology, a cumulative NMOS varactor diode applied to three-dimensional integrated circuits was proposed. Compared with the conventional cumulative NMOS varactor, the TSV-based cumulative NMOS varactor had the advantages of high capacitance density and high integration. The impacts of TSV height, TSV diameter, junction depth and width of source region and drain region on the performances of the proposed varactor diode were analyzed. The results showed that the capacitance density could be increased by increasing the TSV height or TSV diameter. The voltage sensitivity could be improved by reducing the junction depth of the source region and drain region. And by increasing the width of the source region and drain region, the inhibition ability of electron generation by the hole in the channel could be improved. An analytic model was added to the above comparison. Finally, the fabrication process of the varactor diode was given.