南宋食鹽由政府專賣，為政府帶來豐盛的收入。私鹽暢銷妨礙官鹽的銷路，影響到國家的財源；官鹽若發售不出，則造成政府抑配官鹽於民眾，影響到民生，造成民怨，甚至可能激起事變。無論從財政或民生著眼，南宋政府都必須防治私鹽。南宋政府在處理防治私鹽的問題時，態度是複雜的，有各種方式與考慮。政府對於食鹽的生產與運銷過程，有嚴密的法規管理；又頒布有處置私販食鹽的嚴格法令，而且不斷申嚴。此外，政府也加強對犯法者的緝捕，對於執行法令的官員以賞罰加以督促，並增設查緝單位。有時也運用以民間力量組成的保伍，與官府的力量互相配合。然而私鹽暢銷由諸多因素所造成，非嚴禁所能止絕，所以政府有時也會考慮或採取其他方式，和嚴禁互相配合，甚或取代嚴禁，以期能有更好的效果。例如調整食鹽的產額、運輸來源與售價，以期消解民眾運銷、購買私鹽的意願；對亭戶的生活加以安恤，以防止他們產銷私鹽。更有一些官員，認為嚴行法禁對於防禁私鹽未必有利，反而有可能造成對民眾的騷擾，激起私鹽商人的動亂。他們不見得主張完全廢弛鹽禁，卻認為應以寬弛的態度來執行。這樣的主張雖然沒有成為政府全面性政策，但也有地方政府在徵收稅錢之後，默許商人私銷、民眾私買；再有一些地方官，以比較寬大的態度來處理私鹽案件。到南宋晚期，政府財政愈加困難，對鹽利需求愈加急迫，在私鹽大盛的情況下，鹽禁也更為緊縮，終致引起較嚴重的變亂發生。南宋政府面對收私鹽之利和寬私鹽之禁兩者應如何取捨的難題，政策在緊縮和寬弛之間擺盪，但財政的壓力終究使政策趨向緊縮的一方。

The sale of salt was a government monopoly in the Southern Song dynasty, and the government reaped much income from the monopoly. But, the booming sale of illicit salt hindered the sale of official salt, and reduced this source of government finance. When official salt became unmarketable, the government tried to force people to buy it at a high price, increasing the people’s burden. Regarding the government’s finance or people’s life, the government had to guard against the illicit salt activity. This article has two aims: (1) To describe the Southern Song government’s concrete efforts to guard against the illicit salt activity; (2) To clarify that when the Southern Song government and its officials faced the problem of illicit salt, their attitude was complicated, so the word “strict prohibition” is not suitable to describe their considerations and measures.