Among all arbitrage varieties, silver is a very good asset. Compared with other agricultural products and industrial products, silver arbitrage has the following characteristics (1), which is universally recognized. Since the beginning of civilization, silver has played an important role in jewelry consumption and currency trading. (2) Global unified pricing. The pricing of silver is the same in developed countries, developing countries, democratic countries and authoritarian countries. It is precisely because of the uniqueness of pricing that silver spread arbitrage will inevitably return. Compared with agricultural products, industrial products and other products, due to various reasons such as trade protection, the prices of different exchanges are often far apart. (3) Property stability. Compared with other basic assets, the chemical properties of silver are relatively stable. Silver will not deteriorate no matter how long it is stored for hundreds of years, and as long as the purity is specified, the underlying assets of different exchanges can be regarded as the same. (4) Why do investors have obvious price differences for the same commodity? It is precisely because of the existence of different investor groups that they have different expectations for the future trend of commodity prices. Investors in Shanghai Gold Exchange are mainly individual retail investors, while investors in Comex Silver are mainly mature investors. The different investor structure determines that the same commodity has obvious differences in different markets. (5) It has the characteristics of financial futures. In futures arbitrage, if commodity futures are involved, the spread may not necessarily return. If investors want to achieve arbitrage, it will inevitably involve spot delivery, and the process of commodity delivery is relatively complicated. As professional investors, they don't want to involve spot delivery. Taking financial futures as an example, stock index futures are delivered in cash, and there is no problem of spot delivery. Even if the future treasury bond futures are delivered in cash, they can be almost the same as cash delivery, because the liquidity of treasury bonds is very good. For silver, although it is also cash delivery, because silver is the hard currency next to gold in the world, its liquidity is very good, similar to financial futures, which makes silver arbitrage opportunities very many. (6) Silver is a perfect arbitrage variety. Silver has both a complete mean regression similar to financial futures and a higher yield of commodity futures, but the risk is the same as that of stock index futures arbitrage, so it is a low-risk investment strategy.