The effects of gas entry route and blow tank pressure on characteristic of dense-phase pneumatic conveying of pulverized coal were studied in top discharge blow tank conveying system. Additionally，a comparison was made on solid mass flow rate，solid-gas ratio and conveying stability between top and bottom discharge blow tank conveying system. It was found that in top blow tank conveying system，solid mass flow rate and solid-gas ratio first increased and then decreased with the fluidizing gas in the conical section; decreased with the supplementary gas and fluidizing gas in the bottom section; while for the blow tank pressure increasing，solid mass flow rate and solid-gas ratio first increased obviously and then the increasing degree weakened. In the same total conveying pressure drop，there are higher solid mass flow rate and gas-solid ratio for the bottom than the top discharge blow tank conveying systems，but there was little difference in conveying stability between the two systems.