The study serves to explore the core of culture – assumption, in managerial settings within selected firms in China. Specifically, the research is to investigate the existence of managerial assumptions in Chinese privately-owned firms, and examine how these managerial assumptions influence managerial behaviors. This endeavor makes three potential contributions in the field of Chinese management studies. First, it provides another lens, managerial assumptions, rather than values, in order to better explain managerial behaviors. Second, this study develops the initial framework of managerial assumptions in the Chinese context. Third, the revised ethnographic method is formed and this method can also be used in other countries or other industries to explore managerial assumptions. The research was conducted in Guangzhou, Qingyuan and Zhuhai, all within Guangdong province. Data collection and analysis was performed with fifty-one Chinese managers in nine upscale hotels, by using an ethnographic method combining documentary evidence, participant observations, and in-depth interviews. This combined ethnographic method allows this research to explore the underlying interactions and relations between artifacts, values and assumptions, suggested by Schein’s culture model (2004). The thesis extracts and summarizes a framework of ten managerial assumptions and argues that these ten managerial assumptions exist in the deepest thoughts of Chinese managers, and guide them to demonstrate certain managerial behaviors. These ten assumptions are “Following closely the thoughts of one’s manager”, “Family as the heart of one’s success”, “Wisdom comes from experience”, “Honor is for the served”, “Flexibility reigns supreme”, “The whole is always more important than the parts”, “Get more with less”, “The continuity of one’s legacy”, “Ultimate measurement is the scale”, and “Never disrupt ‘harmony’ and ‘Balance’”. These ten managerial assumptions help to explain some anomalies of managerial behaviors which are found in some Chinese management literature such as the leadership and decision-making behaviors, relationships with different parties, performance evaluation of the subordinates, finding successors, and teamwork in firms. Following the presentation of the main results, the thesis compares the ten assumptions with the five categories of Schein’s typology (2004) of fundamental assumptions, and attempts were also made to categorize these assumptions into three levels, including the level of self, the level of managing, and the level of organization.