In recent years the term “smart grid” is emerging in the media. The smart grid delivers electricity from suppliers to consumers using two-way digital technology to control appliances at consumers’ homes to save energy, reduce cost and increase reliability and transparency. In order to operate the smart grid properly, the power system analysis is necessary. The analysis of smart grid is required the power system model. However the configuration of the smart grid is frequently changed. To cope with this situation, power system drawing assistance systems are required. This paper proposes a power system drawing assistance system by using Ruby/Tk. Ruby is a scripting language, in the recent tradition of Perl, Python, and Tcl. Ruby originated in Japan during the mid-1990s and was initially developed and designed by Yukihiro Matsumoto. It allows for a rapid development cycle and the rapid prototyping of applications. In order to the effectiveness of the proposed system, a prototype system is developed. The results show the proposed system is promising the assistance of the power system engineers.