Ever since 2007 when the policy of low fare was introduced in Beijing’s public transport system，the trip rate of public transport has risen and congestion has effectively relieved. As the public transport demand in Beijing has been growing year by year，the yearly increasing financial subsidiaries resulting from low fare system have generated more pressure on the local financial burden，meanwhile，the low fare system derived from high subsidies distorts people’s travel behavior and brings some security problems. So，it is necessary for Beijing to improve financial subsidies for its public transport in many aspects.