Abstract: The remote controllability of loads and the weakness of user-side information security protection make it easy that controllable loads（CLs）are maliciously controlled by attackers,which might affect safe and stable operation of power grid.Firstly,security of risk brought by different kinds of CLs is analyzed,and a control model of distribution network with CLs considering the cyber-attack is proposed.Moreover,an attack model of CLs maliciously controlled is established,and three types of attacks that CLs suffered are defined on the basis of"on"and"off"mode for control.Then,the influence of network delay on attack model is studied by the measurement and statistical analysis.On the basic of the research mentioned above,appropriate scenes are chosen to simulate and analyze the influence on the reliability and power quality of the distribution network when CLs suffer malicious control.The simulation verifies that the controlled loads which reach a certain scale will bring risks to the distribution network and risk consequence is proposed according to different types of attackers.