Abstract: To meet strict requirements which need high voltage input range and power supply noise rejection ability in industrial and automotive electronics fields, a Low Dropout Linear Regulator (LDO) with wide power supply range and high Power Supply Rejection Ratio (PSRR) is designed. A new type of high voltage pre-regulation circuit is proposed, which improves the linear regulation and temperature drift of internal low voltage power supply (LV_AVDD) by using the negative feedback current and Cascode Cross-Coupled BJT structure. At the same time, the PSRR of LDO is further improved by the pre-regulation circuit. The whole circuit is composed of high voltage pre-regulation module and LDO loop module, and is designed based on 0.18 μm BCD process. Simulation results show that when the input power supply range is 10 − 40 V and the temperature range is −40 − 125 ℃, the output of LV_AVDD is 5.574 V, the temperature coefficient is 1.358×10⁻⁵ ℃⁻¹, the linear regulation is 0.763 mV/V. The LDO output voltage is 3.325 V, and the low frequency PSRR reaches −120.1 dB.