The relation between Afghanistan and Pakistan are often unstable. The issues now，such as the continuing instability along the Afghanistan-Pakistan border，the claim of Pakistani support for terrorism，the worsening situation of Afghan refugees in Pakistan，the restrictions placed by Pakistan on trade from Afghanistan，as well as other issues are the root of problems faced by Afghanistan and Pakistan in development of their relations. At the same time，behind the worsening relations between Afghanistan and Pakistan，we can see the influence exerted by the competition and power games between the neighboring countries including the U.S.，Russia，India，Iran，China and other countries. Apart from the conflicts ensuing from the power games played by the neighboring countries over the Afghanistan-Pakistan issues，there are common interests between these countries too，which brings more unpredictability to the development of Afghanistan-Pakistan relations. Afghanistan-Pakistan relations are characterized by lack of mutual trust on many issues. Third parties are the key factor for development of Afghanistan-Pakistan relations. Easing of the tense relations between Afghanistan and Pakistan depends on more mutual trust between the two countries，and more importantly，we need a more extensive dialogue mechanism as well as more trust between the game players in the region.