Bangladesh，China，India and Myanmar are linked by rivers and mountains.The four countries enjoy a long history of contacts and they vary in term of natural endowment and culture.The four economies are also highly complementary.The four countries hold the conference alternatively since BCIM Regional Economic Forum was found in 1999.BCIM have published some proposals and statements which have great impact.The BICM is aimed at mutual benefit and common development.It has achievement on the cooperation in the filed of mechanism，transport，trade，tour and so on.BCIM is an important cooperation mechanism for strengthening links and improving sub-regional cooperation between China and South Asia.However，BCIM sub-regional cooperation is still in the process of development and has a lot of problem.Compared with the new situation of economic globalization and cooperation potential between the four countries，BCIM sub-regional cooperation develops slowly.In order to boost pragmatic cooperation between BCIM，the four countries should strengthen coordination，take advantage and learn from each other.