An assembly of a flash-lamp string system comprising a plurality of flash-lamp strings connected in series so as to form into an elongate lamp string; the elongate lamp string includes at least two different flash-lamp strings in terms of flashing type; the outer shape of the two different flash-lamp strings is the same; the bulb socket and the bulb assembly of every aforesaid flash-lamp string can be mounted together within the same flash-lamp string; in other words, the bulb socket and bulb assembly can not be exchanged with that of the different type of flash-lamp string in order to avoid overload of power supply.