Abstract: According to the national standards (GB 14922 - 94), the microorganisms and parasites of the various - aged rabbits in the opening environment were investigated. The results indicated that the rabbits were infected mainly by P. multocida ,B. bronchi sept ica and Eimeria Stiedae which the infection rate of P. multocida in the adult and the young rabbits was 40% and 32%，the infection rate of B. bronchiseptica increased with age (23. 7% in young,72% in adult) ,and the rate of Ehneria Stiedae infections decreased with increase of age(50% in young,25% in adult). The other items which had been investigated were showed negative or slight positive.