In order to resolve the key problem of preference representation of negotiator in multi-party and multi-attribute Negotiation Support System (NSS), a multi-party and multi-attribute negotiation support system based on preference representation of artificial psychology was proposed. Firstly, a model of artificial psychology based on cloud model was proposed. The fuzziness and randomcity were reflected fully in the model. Besides, its process of negotiation and suggested resolution of negotiation by means of media were also given. Lastly, the prototype of system and test were provided. The result of test in negotiation support system can predict the preference of negotiator.