With the increase in Internet applications, traditional business analysis systems are gradually failing to meet the needs of enterprise data handling and decision making. With the help of personalized and digitized scientific data analysis techniques, there is an increasing need to combine traditional business analysis systems with big data technologies to enable companies to make appropriate decisions based on the latest data. The purpose of the thesis is to examine the influence of big data on decision-making quality based on the data from Alibaba Group in China. Using primary data collected from professional statistics website and the company's official website, as well as by compiling and analyzing data from market questionnaires for different customers, we are able to determine the impact of big data on the quality of decisions and how the market tests the quality of decisions after they are implemented.