A bandgap reference is designed with high order curvature compensation method, which has advantages of simple structure, good energy dissipation capacity and an optimized temperature coefficient of the reference voltage. Taking advantage of the nonlinear characteristics between leakage current and gate-source voltage when NMOS is working in the sub-threshold region, the proposed method decreases the temperature coefficient of reference voltage by introducing a high order curvature compensation current of which the temperature coefficient is contrary to reference. The formula of the compensated reference voltage is derived. Based on the 0.18 μm BCD process, the simulation results show that temperature coefficient of reference is 6.94×10^-6 in the temperature range of -40 ℃~150 ℃, linear regulation rate is 0.033% in the supply voltage V_DD range of 2.5~5.0 V, the supply current is 7.36 μA with 5V power supply, the power supply rejection ratio(PSRR) is 77.4 dB at the Tipical corner(TT). The theoretical analysis results of reference agree well with the simulated results. The bandgap reference voltage source shows excellent performance vias the high order compensation, which satisfies the requirement of low power consumption and low temperature drift in bandgap reference designing.