Go was invented in ancient times. It is a game with a long history and has been passed down through generations. Now, although the rules are different from the past, Go has always been a popular game in many countries. The rules of Go are simple and clear, but there are many ways to play it. So Go is considered one of the most popular and interesting board games in the world. In this thesis, we propose a process to build the 4x4 Go endgame databases. We use the AGA scoring rules and try different rules, including no cycle is allowed and only allows length-2 cycles formed by ko. We analyze the impact of prohibiting cycles on the endgame databases we build. Finally, we build the endgames for 2x2 Go, 3x3 Go, and 5x5 Go and observe the relationship between the board size and cycle dealing rules.