Recently, the electrical characteristics for the short channel MOSFETs (Metal-Oxide-Semiconductor field effect transistor) have become important because of the increasing density of LSIs (Large Scale Integrated Circuits). One of the methods to understand the characteristics of the short channel MOSFETs is the two-dimensional analysis of the MOSFETs, and many studies about threshold voltage and other items have been made by using the two-dimensional method. In this paper, the drain breakdown characteristics for the short channel MOSFETs are calculated by the two-dimensional analysis method. Consequently, one of the phenomena for the short channel MOSFETs, that the breakdown voltage decreases with increase in gate voltage, is reduced to the difference of the electric field strength distribution from that of the long channel MOSFETs. This variation of the electric field distribution is caused by the strong influence of the electric field from the drain upon the considerable region in the substrate of the short channel MOSFETs.