The present invention involves to a festival lamp string comprised of cords, a certain number of sockets and coordinated illuminators; said illuminators are individually and sequentially connected with the cords, said socket is molded over the contacting portion of the illuminator and the cords by filling package. In manufacturing, firstly connects the sockets to the cords sequentially and individually, then cover the decorated cap on the illuminator respectively, next place the assembled cords and illuminator and the decorated cap into the inside of jetting molder so that the contacting portions of the cords and illuminator and the decorated cap are exactly laid on the die cavity, finally inject resinoid into die so as to fill up all the cavity of the die to form a socket covering the contacting portions of the cords and illuminator and the decorated cap, the temperature of the resinoid is lower than 80° C., so a festival lamp string with decorated cap is manufactured. It possesses some features, such as simple structure, less parts and good tightness which can be used in wider range whatever commercial power or not, wherever inside or outside, and it is also to simplify operation, improve work safety and up-to-standard rate, and suit to industrial scale production.