The paper observes the serious condition of security in the Northeast Asia and develops further study on the building of northeast Asian security cooperation mechanism. The author proposes his own opinions on the following aspects –the general view on the endeavor from Korea-U.S. alliance, U.S-Japan alliance;and northeast Asia countries in the building of "regional" interests community; and the natural trend of six-party talks becoming the prototype of the northeast Asia Security cooperation mechanism. The Paper ends with the illustration that Asian security cooperation mechanism in practice should be the product of interest coordination, the overall interests of the northeast Asia, regional countries (including North Korea) and the countries who have important interests (such as the U.S.) should be considered properly. Only by which, the authoritative and institutionalized multilateral security cooperation mechanism can be eventually set up with the object of common security, on the basis of common interests; and accordingly a brand new northeast Asia security order will be built with lasting peace, stability and prosperity. <<