Global safe assets decrease after financial crisis, which relatively improves Japanese debt position and which becomes one of risk prevention tools in global financial market, because the ratio of Japanese long-term government bonds net amount to GDP is high, however, the national debt credit is damaged, and Japanese sovereign credit rating is down-graded. Based on the feature of Japanese domestic capital circulation, the reason for a Japanese enterprise to become a big depositor is not the increase of enterprise’s earnings but is compelled by the pressure of adjusting balance sheet to make investment willing decrease, thus, Japanese Government has to continuously increase national bonds issuance to make up fundraising subject default. The short-term Japanese debt maturity structure and increasing interest burden make its market interest rate risk bigger, meanwhile, the scale of Japanese Central Bank bonds purchase is swelling, which constantly challenges the limitation of financial regulation, as a result, financial deficit monetization risk is hidden in it. From long-run perspective, after Japanese bubble economy burst out, the bubble removal process of Japanese assets is the bubbling process of Japanese debt, thus, the sustainability of Japanese bonds has huge risk under the premise of the uncertainty of Japanese financial reform prospect and the non-recovery of Japanese enterprise investment demand.