In order to study the variation law on the mobility control ability of hydrophobic associated polymer（HAP）based ASP flooding during long distance migration in porous media，a physical sand-packed model of 30 meters long with the average gas permeability of 872×10^-3μm² was set up for oil displacement experiments. The mobility control ability of HAP based ASP system was analyzed as compared with conventional ASP flooding. The results showed that the HAP based ASP system had difficulty in injection and lower mobility control ability than conventional ASP system during long distance migration. The HAP based ASP system had higher measured values of viscosity and lower pressure near inlet，which indicated that the net structure formed by association could not keep in the narrow space of pore. In second type oil layers，the minimum of the viscosity of displacement agent was 23 mPa·s for the sweep of smaller pores. The effective migration distance of ASP system was around 40% of the well spacing under experiment conditions，where the viscosity was not lower than 23 mPa ·s.