The most people in the study tradition economic theory often thought the market competition degree is intense promotes the essential condition which the social welfare increases, but recent researchers have already discussed the implications of entry on social welfare to a large extent and found that entry does not increase welfare always. Previous works are useful the input suppliers and final good producers are vertically integrated; those analyses may not be suitable in vertically separated industries. Let us consider an economy with upstream and downstream markets, there are upstream firms producing a homogenous input and downstream firms producing homogenous goods to final consumers. We discuss the upstream and downstream department manufacturers the market turnover condition how to affect manufacturer of competition behavior this vertical correlation industry, the number of firms, industrial profit and the social welfare. This model analysis under free entry in the upstream market supposition or not, we find that entry in the downstream market always increases social welfare. But we discussed the downstream market when does not permit the firm free entry under the supposition, after upstream firms free entry social welfare respectively will receive the downstream firm¡¦s entry cost, the number of downstream firms or the number of upstream firms three influences.