In order to explore the possibility of β-Cyclodextrins(β-CDs) in high-efficient pesticides utilization, environmental protection and other areas, the β-CD /chlorpyrifos inclusion complexe was prepared by grinding, ultrasonic and the saturated aqueous solution method.The solid inclusion complexes and inclusion behavior in the β-CD solution with chlorpyrifos were qualitatively confirmed using UV spectrum, differential thermal analysis and infrared spectroscopy. The results show that saturated aqueous solution method was the best, and the inclusion rate was 45.8%; the best reactionconditions were:the ratio of chlorpyrifos to β-CD was 1:1 (mole ratio), thermostatic mixing time was 3h, inclusion temperature was 60 ℃. Validation results show that the inclusion complex was formed in the reaction and the inclusion ratio was 1:1, and stability constant K = 33.33 L/mol, the Gibbs function △G=-8.69 KJ/mol.This study proved that the stable β-CD/chlorpyrifos inclusion complexe was formed,some functional groups of chlorpyrifos molecular came into the β-CD cavity.