This study investigates and analyzes how maritime jurisdiction is regulated by the written constitutions of 147 coastal countries in the world, and the results are as follows: First, as to whether or not the concepts of maritime jurisdiction are mentioned in the constitution, the concepts of maritime jurisdiction are not mentioned at all in the constitutions of 80 countries, and only one or more concepts of maritime jurisdiction are mentioned in the constitutions of 67 countries. It is only in the Americas that more than half of the countries surveyed have one or more concepts of maritime jurisdiction mentioned in their constitutions. Therefore, it cannot be said that the rules of maritime jurisdiction under the Constitution are spread all over the world. Second, with respect to the number of concepts of maritime jurisdiction mentioned in the Constitution, the average number of concepts mentioned in the world is 2.63, which is less than half of the total of 6. The average number in the Americas is just over half of the total of six. Therefore, the rules of maritime jurisdiction in the constitution are not very abundant, and this is especially the case in Asia and Europe. Third, in relation to the three core concepts of maritime jurisdiction, namely, the territorial sea, the continental shelf and the exclusive economic zone, the number of 26 countries referring to all three and 17 countries referring only to the territorial sea is considerably more than half of 67 countries surveyed. Therefore, it can be said that regulations of maritime jurisdiction is relatively systematic in the constitution. Fourth, in relation to what matters are regulated by using the concepts of maritime jurisdiction in the Constitution, that is, in relation to the usage of the concepts of maritime jurisdiction, there are three types. As one of such uses, the concepts of maritime jurisdiction are used to establish and declare the extent or breadth of maritime space under jurisdiction in 50 countries. The number of these countries is relatively many in the Americas and Africa, but very few in Europe and especially in Asia. As another such usage, in 18 countries, the concepts of maritime jurisdiction are used to allocate maritime jurisdiction within national organizations (eg, between federal and state or between central and local governments). As the other of such usage, in 31 countries, the concepts of maritime jurisdiction are used to prescribe the attribution of ownership of natural resources existing in maritime space. Fifth, with regard to how the Constitution regulates the extent or breadth of maritime jurisdiction, with regard to the method of regulation on the extent or breadth of maritime jurisdiction, the constitutions of 28 countries entrust the laws to set it. However, the constitutions of 27 countries make no mention of the extent of maritime jurisdiction. The extent of maritime jurisdiction is set by the Constitution itself in only six countries. The cases of Asia and Africa are considerably similar to the global trend, but the constitutions of the majority of countries surveyed in the Americas mandate that the extent of maritime jurisdiction be set by laws.