The effect of substrate negative bias V B on the gate-induced drain leakage (GIDL) current is studied. It is found that the negative V B leads GIDL current curve shifts upwards. The shift of GIDL current ΔI D /I D increases with increasing |V B |. The GIDL current at V G =−0.2V (in the low field region) increases with increasing |V B | more largely than that at V G =−1.2V (in the high field region). This is because that the negative V B results in the additional GIDL tunneling current in the lateral direction and it has the different effects on the low field region and high field region. It is also found that ΔI D /I D at V D =0.8V is larger than that at V D =0.4V under V G =−1.2V and is smaller than that at V D =0.4V under V G =−0.2V. This ascribes the different roles of the GIDL vertical tunneling current and the GIDL lateral current induced by negative V B on the whole GIDL current.