A seven-color light emitting module and a seven-color decorating lamp string comprising the same. The seven-color light emitting module includes a lampshade made of a transparent plastic or synthetic resin, and a lamp socket on which three colors self-flashing light emitting diode, a zener diode, a current limiting resistance and a double-side printed circuit board (PCB) are sealed. The three colors light emitting diodes connect with PCB and connect with the zener diode in parallel. One end of the zener diode or two ends of the zener diode connects with the current limiting resistance in series. A transparent epoxy resin or silicon glue is filled in the lampshade. The seven-color decorating lamp string include a power supply plugs, a power supply module which has a PCB and a rectifying and filter circuit connected by wires and a plurality of said seven colors light emitting modules.