Inspired by the idea of physical fields, the discussion platform of each blog or public opinion event is regarded as an opinion field, an opinion attraction potential function is used to describe the interactive attraction from all net citizens in a public opinion field, the directional opinion attraction network of the net citizens is established based on the timevariant point state of the cyber citizens, and then the opinion leader is discovered by detecting the nodes of the net citizens with high attraction potential. This algorithm can effectively avoid the disadvantages of dependency relationship indeterminacy among the net citizens in traditional opinion leader discovery algorithm based on link or reply relation.