Abstract: Acaricidal activities of twenty-seven plants extracts against Tetranychus cinnabarinus were measured in laboratory using slide-dip method. Our results showed that high acaricidal activities were observed in 8 herbal extracts at 48 h post-treatment. The contact toxicities of these 8 herbal extracts against Tetranychus cinnabarinus were further determined using a series concentration of various extracts. Among the 8 herbal extracts, chloroform extract of Pogostemon cablin (Blanco) Benth had lowest LC50 value (0.5380±0.1319mg/mL). Petroleum ether extract of Quisqualis indica L. was in the second place with LC50 value of 0.5554±0.1088 mg/mL. This was followed by Herba Polygoni Avicularis chloroform extract with LC50 value of 0.7153±0.1253 mg/mL. Then, the other eight herbal extracts were arranged in decrease sequence according to their LC50 value as follows: Semen Hydnocarpi Hainanensis chloroform extract (0.7582±0.1038mg/mL), Semen Hydnocarpi Hainanensis petroleum ether extract, Herba Polygoni Avicularis.petroleum ether extract, Millettia reticuiata Benth petroleum ether extract, Spina Gleditsiae petroleum ether extract.