Digital currency contract is the reform of traditional futures contract. There are unified risks, such as the need for margin and the risk of short positions. Moreover, the digital currency contract is worse than the traditional futures because the digital currency contract can't be delivered in kind, which means that once it goes against the order direction and breaks through the minimum margin ratio, it must be forced to close the position, and there is no other way, which leads to greater risks. Now some exchanges, such as Bitoffer, have launched bitcoin option products, which can amplify the income without the risk of short positions.