The object of the surface treatment is very extensive and widely be used. Not only from traditional industries to high-tech industrial precision but also from the metal surface to the non-metallic plastic surface. Officially, the major function of the surface treatment makes the material more proofed against corrosion and abrasive. Also it marks the material be more heated-resistant. The most important thing is extended to life time of the material. In sum up, there is no doubt the definition of the “surface treatment is all the changes in the physical surface of materials, mechanical and chemical properties of the processing in terms of improving the properties of the material surface, the gloss appearance and other value-added products. The main article of the technical report is illustrate the method of painting by solvent. Based on the case study of W company indicate and focus on how to best improving the production model of the operation in line and the excellent parameters setting of its equipment. In the early stage when the W company doing the product development. They do trial and error in order to optimize the best parameter of its production process. However, just could not effectively shorten the lead time of the production and could not control the low yield rate. To be more precise, the figures of the low yield rate reach to 44.2 %. Therefore, it is necessary to conduct the method which is could efficiently increase the yield and shorten the low yield rate when developing new products. Regarding to the case study of W company, Set up the target purpose of the W company, in order to figure out the key factors of how to implementing fit parameters successfully, The use of experimental design and statistical quality control techniques tools in various stages such as the characteristics to be a result of the whole maps, quality function deployment, causality matrix and failure mode analysis to identify and analyze these key factors to meet its purpose. In conclusion, There are four key factors of improving the quality as below : (1)Base coating viscometer.(2) Air pressure of spray gun.(3) The after treatment of the cleaner uses the pharmaceutical is residual.(4) The SOP of product operation. Regarding factors of item (3) and (4). These two factors are caused by human factors. However, these two factors might be gain the significantly improves after educating and training. Thus, it is not including to the report of the improvement methods. According to the studying, It is illustrate the base coating of the process is the most important key factor when improving the operation process. There are four ingredient of this method are contains baking temperature, coating viscosity, pressure spray guy and type of solvent. The result figure out the significant factors is the coating viscometer and the type of solvents. Conversely, there is no any meaning of the rest factors. Due to the baking temperature is high, volatile solvents, coatings and material adhesion performance is good. in sum up , it is come out the best combination of these four key factors. The combination of parameter values presented in the report, the cases against companies small batch test, the test results were analyzed to improve the effectiveness. It is consists of two parts : (1) Fail rate analysis (2) X-bar and R control chart analysis. After the actual experiment, it is successfully reduced the low yield rate from 44.2 % to the 14.3%. It is just meet the customer need indeed. After improving of X-bar and R control chart almost all within the control limits , it is also indicate that the process is stable and close to the center of the process specification values . This case may be used as reference solutions related to industries during problem solving.