The present invention provides a LED decorative light string that comprises one or more branch circuits, each of said more branch circuits is connected in parallel with each other, and then connected to a common power supply wire for importing operational voltage; each said branch circuit comprises a quantity of light groups, and said quantity of light groups are serially connected in turn; each said light group comprises two or more LEDs, wherein at least one LED is connected in parallel with other LEDs in reverse direction, said other LEDs are connected in parallel in the same direction. The LED decorative light string of the present invention has the advantage of more economical, more reliable in performance, longer life span.