This paper presented a current reference in wide voltage and temperature range based on BCD technology. Based on the feature that the TC of the on-chip poly-silicon resistor was process-insensitive, the on-chip resistor was set as the reference current defining element. First, the temperature characteristic of the on-chip resistor was analyzed, and a reference voltage whose TC was equal to the resistor’s was designed and applied on the resistor. Then, a reference current with a very low TC could be achieved. The leakage phenomenon of the parasitic element of the triode under high temperature was analyzed, and the stability of the reference current under high temperature was improved by adding a compensation transistor. This CS was based on 0.35 μm BCD process. Simulation results showed that the output current was 250 μA and the TC was 9.3×10-6/℃ within 6.5~36 V supply voltage and -55 ℃~125 ℃. The amount of current change caused by the power supply was less than 62 nA.