Hexadecanal, as a key component or synergistic substance of sex pheromones in a variety of lepidopteran insects (such as cotton bollworm and tobacco green worm), is released by female glands to regulate the directional behaviour of male insects, and has been used as a pheromone synergist in the trapping system and mating interference technology of agricultural pests, showing high efficiency and low ecological risk in the green prevention and control of cotton, tobacco and other crops.