For extra-low permeability reservoirs, with a permeability of about 0.3×10^-3μm², fluid low and production performance in cores were studied. A long core holder with a multi-location piezometric measurement was specially designed. An artiicial long core, about 700 mm long and with a cross section of 45mm×45mm, was used. In the experiment, pressure distribution along the core can be measured in real time. Single phase low in the core was investigated. Different modes of production in long cores were also simulated including natural depletion, water looding, and advanced water looding. Through physical simulation, low parameters were collected and production characteristics in extra-low permeability cores were studied. From experimental results, it can be seen that fluid low in extra-low permeability cores is different from that in high permeability cores. Transmission of pressure in extra-low permeability cores is very slow, and it needs a long time for the pressure to become stable. The distribution curve of pressure along the core is nonlinear and the production rate in extra-low permeability reservoirs decreases sharply. The development effects of different production modes in extra-low permeability cores were compared with one another. Among the production modes, advanced water looding has much potential for effective development of extra-low permeability reservoirs. Natural depletion and conventional water looding can also be used in early production periods. In addition, the countermeasures and some ideas especially for the potential development of extra-low permeability reservoirs are suggested.