The high volatility of digital currency makes it impossible to fully perform the functions of currency, so blockchain practitioners have created "stable coins". Stablecoin Stablecoins, as the name implies, is a digital currency with a relatively stable price of legal currency. It uses some model designs to ensure that the price of the stable currency fluctuates in a small range in the price of the underlying legal currency, so as to ensure that the price of the digital currency market fluctuates violently. It plays a good role in fund hedging, asset storage, payment and settlement and other functions.

The ideal stable currency is an encrypted digital currency with strong trust relationship, self-government, but stable value. This article attempts to discuss the birth of stablecoins, the mechanism of stablecoins, summarize the advantages and limitations of existing mechanisms through the evolution of various representative currencies under different mechanisms, and propose the prospects for the development of stablecoins.