The function call diagram is the important tool of ensuring software reliability and safety. Building a function call diagram is very crucial in understanding the program and ensuring software reliability. After summarizing the current popular build tools for function call diagram generation, based on the Clang structure analyzer, according to the characteristics of high level language, using SVG graphics display technology, we design a new method for function call diagram display. Experiments show that the method can generate the function call diagram accurately, as well as improve the drawing efficiency and quality of diagrams, in order to provide graphics support for the reliability of software.