The invention relates to a spark plug with a precombustion chamber structure. The spark plug includes a tubular metal shell, an insulator fixed in the metal shell, a central hole arranged in the insulator, a central electrode mounted in the central hole and a side electrode connected to the metal shell. A spark plug gap is formed between the central electrode and the side electrode. A precombustion chamber shell is connected to the lower end of the metal shell. A precombustion chamber is defined by the lower ends of the precombustion chamber shell and the metal shell. The spark plug gap is located in the precombustion chamber. The precombustion chamber shell is provided with multiple upper spray holes and multiple lower spray holes. The multiple spray holes are located on the upper side ofthe multiple lower spray holes. The spark plug with the precombustion chamber structure can form up-down stratified jet flames with different spray cone angels during a combustion process of an engine, thereby accelerating the combustion of mixed gas, effectively solving the problem of decrease of burning rate when a gasoline engine adopts a Miller/Atkinson cycle, ensuring the ignition stability,and avoiding carbon deposition blockage.