Abstract: The present disclosure relates to decorative lamps, and in particular to a three-line four-way light string and control system thereof. The three-line four-way light string and control system thereof comprises signal lines L1, L0, L2, a plurality of LED lamps are connected between the signal line L1 and the signal line L0 in parallel, and a plurality of LED lamps are connected between the signal line L2 and the signal line L0 in parallel. The three-line four-way light string and control system thereof provided by the present disclosure can be produced by utilizing a full mechanization manner so as to have high yield and accuracy, save raw material and energy consumption, have a little pollution and be applicable to mass production.