A linear constant current drive circuit, including a first end of an LED string is connected to one output end of a rectifier bridge, a second end of the LED string is connected to one end of an energy storage capacitor by using a first switch subcircuit, and the other end of the energy storage capacitor is connected to the other output end of the rectifier bridge; one end of a second switch subcircuit is connected to a junction between the first switch subcircuit and the energy storage capacitor, and the other end of the second switch subcircuit is connected to a tap end of the LED string; and one end of a third switch subcircuit is connected to the second end of the LED string, and the other end of the third switch subcircuit is connected to a junction between the rectifier bridge and the energy storage capacitor.