Traditionally, the Common Law System exercises a legal separation of marital property regime between husband and wife; this regime still has interpretation theory value for functional comparison to that of China. The husband-wife personality integration in the early days of the Common Law System goes back to the original agency of necessity similar to that of the daily family agency of the Civil Law System; the aim was to strengthen marital coherence rather than protect creditors. The “daily family needs” should be identified without excluding the husband-and-wife separation period, and be based on the consumption level during the time that a couple have lived together. The current mainstream mode of the Common Law System starts from the “Consensual Approach” under the legal regime of separation of property between husband and wife, and limits the “Purpose Theory” to cases of insufficient consensual evidence. Moreover, this mainstream mode is supplemented by the “Presumption Theory” that only exists as a method of proof, and is similar to the current Chinese position of co-debt and co-signing. When a nondebtor consents a debtor to borrow money in the name of husband and wife, this consent can be used as a yardstick to determine their marital community debt and to identify the nature of various debts in the context of marital community debt.