Abstract: Harmonia axyridis(Pallas) is one of the important predations, and it can prey many kinds of aphids, it has very useful foreground in biological control. The functional responses of Harmonia axyridis(Pallas) on three species of aphids[ Chaitophorus populeti (Panzer), Rhopalosiphum padi (Linnaeus), Lipaphis erysimi (Kalteback)] were investigated in the laboratory. The results showed that the 4th instar larvae had the biggest daily predation capacity，followed by adults and the 3rd instar larvae .The smallest is the 1st and 2nd instar larvae. The functional response of Harmonia axyridis(Pallas) to aphids was simulated with models of Holling-Ⅱ.