Abstract: Cloudy bayesian network was proposed by combining cloud model and bayesian network,and a threat asses-sment model was built based on cloudy bayesian network．Firstly,the bayesian network structure was designed according to the background,and continuous observation node was transformed into cloud model．Secondly,the observation variable value was input to the cloudy bayesian network,reasoning out the probabilities of target which belongs to each threat level．Finally, repeat reasoning was made to eliminate the influence of target information uncertainty on the overall threat grade,and the final threat grade was obtained by probability-composing formula．The validity of the method was checked by simulation for aerial targets threat assessment against a background of joint air defense operations.

Key words: Threat assessment,Cloudy bayesian network,Cloud model,Bayesian network,Information fusion