In this paper, the transmission characteristics for Rb, 85 Rb and 87 Rb Faraday optical filters at 532nm that can be used to detect the practical and important frequency-doubled Nd:YAG laser are analyzed and discussed. The theoretical model of an excited-state Faraday optical filter based on the hyperfine structures of atomic system in the intermediate field, what is to our knowledge, is firstly reported. This model predicts that the peak transmission is approximately 50% with an equivalent bandwidth of less than 3GHz for filters operating on the 5P 1/2 →10S 1/2 transition in Rb, 85 Rb and 87 Rb vapors, respectively. Moreover, the transmission property of 87 Rb atomic vapor is superior to that of Rb, 85 Rb atomic vapors, which makes it more suitable for the operation material of Faraday optical filters by comparison with natural Rb vapor.