There is also a step-by-step method of calculating costs by product type and processing steps involved. Many enterprises use this method, such as metallurgy, textile and other large-scale continuous processing multi-step enterprises, and such as machinery manufacturing, assembly and multi-step production enterprises. The step - by - step method can be seen as simultaneous or continuous at each production step using the variety method. In cost management, because the cost of different production steps of different enterprises is different, we distinguish the step by step method and the step by step method. The cost from semi-finished product to finished product is calculated step by step, until the finished product is completed, the cost of the product is complete. For the export market of semi-finished products, the analysis and evaluation of semi-finished products and the cost information and management of semi-finished products of many enterprises of deep processing products are applicable to the step method. The calculation method of step by step carry-over is to carry forward the cost of semi-finished products step by step and calculate it until the final production step