An LED light string assembly has a plug for providing a low DC voltage, an extension socket, a light string connected between the plug and the extension socket. The light string has multiple LED Christmas bulbs connected in parallel. Each LED Christmas bulb includes an LED and a resistor connected in series. Even one of the LED Christmas bulb burns out, all the remaining LED Christmas bulb of the light string will not be affected and still can be normally turned on as required to generate light.