Abstract: The Civil Code establish the significance of the mode of "joint signing of community debt", but scholars disagree about its legitimacy and applicability. Theoretically, the dispute over the legal norms of "joint signing of community debt" by both spouses in China stems from the positive and negative views on the moral, economic and necessity aspects. In judicial practice, there exists an imbalance between litigation rights and substantive rights in norms of "joint signing of community debt" by both spouses. Therefore, the "purposive intervention mode" in which the state selectively intervenes in the internal behavior of the family has legitimacy in the activity of optimizing the normative function of the "joint signing of community debts" by both spouses. On the one hand, the "purposive intervention mode" requires that the optimization activities be guided by "consequentialism";on the other hand, it requires progressive promotion in tackling the morality bottom line, failure of family adjustment function, and dissolution of the marital community and awakening of awareness of individual rights.

Key words: family law, purposive intervention, joint signing of community debts, legitimate applicability, consequentialism