A touch-operation-based dynamic geometry system: design and implementation. GeometryTouch is a dynamic geometry software system with touch operation. Developed by JavaScript and SVG, GeometryTouch is a Web-based application which can run on browsers of mobile devices. When using GeometryTouch, users can draw geometric figures and create or modify geometry-based interactive manipulatives. A virtual cursor is designed to implement precise operations in GeometryTouch. Geometric operations consist of 4 continuous actions and it is a challenge to implement the action of “the first point confirming”. Three methods have been investigated to tackle the problem in the paper.