This invention relates to a kind of fireworks with a fan-like flash posy set-off effect including several emission tubes put slanting and arrayed in line, the emission tubes of each line are arrayed in fan, quick-ignition connection is applied among tubes in a same line and slow-ignition connection is applied at ether end between two lines, emission powder and powder posts made of set-off powder are set in the tubes, said set-off powder includes a core, an ignition powder, the weight percentage of the composition in the core is: CuO 15-45%, BaNO3 15-45%, MgAl alloy powder 15-50%, dextrin 1-3%, the weight percentage of each composition in the ignition power is: KNO3 35-65%, sulfur 2-15%, charcoal 20-50%, dextrin 4-8%, said core is mixed in terms of 20-50% weight ratio and the ignition powder is 50-80%.