Key laboratory in universities is the platform of science and technology innovation and the key contents of disciplines construction of university. The article argues the function of key laboratory in disciplines construction of university from three aspects including fostering qualified personnel，scientific research and crossing and infiltrating of disciplines. In view of the main problems existing in our present disciplines construction of key laboratory，in the disciplines construction of key laboratory，we should adhere to the advantages of characterizes of subject，well do scientific and technological innovation，talent team construction，laboratory opening and infrastructure construction for forming the benign cycle between laboratory construction and disciplines construction and promoting disciplinary building and development