Mars Ecosystem is a new decentralized Stablecoin paradigm that addresses the fundamental problem of Stablecoin Protocols, known as the Positive Externality Problem, by internalizing the positive externality. It achieves this by integrating the creation and use of stablecoin within a single ecosystem. The relationship between Mars Stablecoin and Mars DeFi primitives creates a positive feedback loop, generating a flywheel effect. The stability and liquidity of Mars Stablecoin are supported by the Mars Ecosystem Token (XMS) and the Mars Treasury, which is funded with multiple types of cryptocurrencies. In addition to integrating with existing DeFi protocols, Mars Ecosystem also introduces Mars Swap, Mars Stableswap, and Mars Money Market to provide value to Mars Stablecoin users and XMS holders. XMS holders have governance rights and manage the Mars Treasury. Furthermore, XMS can be staked at DEX to earn a portion of the transaction fees generated. Mars Swap is a Uniswap-type AMM DEX that offers deep liquidity between Mars Stablecoin and all other tokens.