The invention provides a BCD semiconductor device and a manufacturing method thereof, comprising a first high-voltage nLIGBT device, a second high-voltage nLIGBT device, a first high-voltage nLDMOS device, a second high-voltage nLDMOS device, a third high-voltage nLDMOS device, The first high-voltage pLDMOS device, low-voltage NMOS device, low-voltage PMOS device, PNP device and diode device, high-voltage nLIGBT device, high-voltage nLDMOS device, and high-voltage pLDMOS device all adopt dielectric isolation to realize complete isolation of high-voltage and low-voltage devices. The invention is implemented on a substrate Monolithic integration of nLIGBT, nLDMOS, low-voltage NMOS, low-voltage PMOS and low-voltage NPN, the isolation area composed of dielectric, second conductivity type buried layer, dielectric groove and first conductivity type injection region realizes high and low voltage full dielectric isolation on the integrated chip , to avoid the high-voltage and low-voltage crosstalk problem, the multi-channel design is adopted in the six types of high-voltage tubes, which can effectively increase the current output capacity of the high-voltage tubes.