The　evolvement　process　of　hierarchies　of　simplified　urban　road　networks　with　different　areas　and　land　utilization　structures　was　investigated　by　computer　simulation.　The　self-organization　system　framework　of　the　hierarchies　of　urban　roads　was　established.　The　difference　of　total　traveling　time　and　number　of　accidents　before　and　after　the　updating　of　the　hierarchies　were　regarded　as　the　guide　line　that　whether　the　road　hierarchies　should　be　updated.　Matlab　software　was　used　to　update　the　road　hierarchies　until　the　network　achieving　stabilization.　Six　road　networks　with　different　areas　were　studied　to　reveal　the　self-organization　phenomenon　of　road　network.　It　was　found　that,　in　the　circumference　of　high　hierarchy　roads,　other　land-use　types　take　a　small　proportion;　in　the　circumference　of　road　networks　with　the　same　area,　different　land-use　types　have　consistent　distribution.