PT. Asiatex Putra Mustafa is a manufacturing company that produces sarung tenun. Recording is done only with a piece of paper and there is not bookkeeping. The time requires the company to continue to grow, so continuous improvement is needed by the company. This study aims to create an application of accounting system that consist of purchase system, production system, and sales system that can help the problem. Rational Unified Process is a system development method used in this study. There are four phase in the RUP, they are inception, elaboration , construction and transition. System modeling language used is UML (Unified Modeling Language). UML diagrams used in this study are use case diagram, activity diagram, sequence diagram, and class diagram. System testing is done with a black-box methods that only tested the way of system functions. The system has been built is able to assist in recording, calculations and result reports realtime.