With the deepening integration of information technology and enterprise management, more and more discrete manufacturing enterprises begin to use ERP system to manage the company's sales, procurement, production, warehousing and finance. Cost is the monetary form to measure the consumption of various manufacturing resources, is one of the criteria to evaluate the efficiency of ERP implementation, and is also the main index to explain the level of enterprise technology and management. This paper mainly introduces a single cost accounting system based on the secondary development of ERP data. Through this system, the manufacturing and labor costs of a product can be calculated accurately, and the accuracy of product quotation can be effectively improved to a certain extent.