A high voltage device includes: a semiconductor layer, an isolation structure, a first deep well, a second deep well, a drift well, a first well, a second well, a body region, a body contact, a high voltage well, a gate, and a source and a drain. The high voltage well is formed in the second deep well, and the high voltage well is not in contact with any of the first deep well, the first well, and the second well, wherein at least part of the high voltage well is located right below all of a drift region to suppress a latch-up current generated in the high voltage device.