Cross-variety arbitrage refers to arbitrage trading by using the contract price difference between two different but interrelated commodities, that is, buying a commodity contract in a certain delivery month and selling another interrelated commodity contract in the same delivery month, so as to hedge and close the position at the same time at a favorable opportunity. The core strategy of cross-species arbitrage is to find a relatively stable relationship (difference, ratio or other) between two or more different but related commodities, and take related reverse operations to obtain profits when deviating from the normal track. According to the relationship between arbitrage commodities, cross-species arbitrage can be divided into related commodity arbitrage and industrial chain cross-species arbitrage.