Many programming tasks require programmers to modify similar program elements continuously. It will take some time to find out the next element to be modified without missing the necessary modifications, and it is too much hassle to select the text to change each similar element. To improve these problems, we extracted all possible matched elements by using the similarity patterns from recently modified elements. The sub syntax tree comparison is employed to extract similarity patterns. As a tool, SimilarHighlight can give programmers some suggests that program elements are similar to the last selected elements and might be modified at the next modifications. The elements will be highlighted and the text of the next element can be selected immediately for modify by shortcut keys. In addition, the tool supports C#, Java, C, JavaScript and other languages in future.