This paper adopts an exploratory case study method, taking the entrepreneurial experience of six portfolio entrepreneurs who switched to mask production industry during the epidemic period, to explore deeply the process and mechanism of entrepreneurial motivation forportfolio entrepreneursbased on relationship network theory, and reveal main influence paths of different relationship network types on the formation of entrepreneurial motivation. The study shows that under uncertain environment, fear of failure may replace economic motivation as the primary entrepreneurial motivation of portfolio entrepreneurs. After the original motive of a portfolio entrepreneur is formed, the original motive will be screened or tested by reality in the stage of motivation evaluation. As a result, the original motive does not necessarily become the real motive of the portfolio entrepreneur. Different relationship networks of portfolio entrepreneurs play different roles in the formation of entrepreneurial motivation in the process of motivation evaluation:Portfolio entrepreneurs who mainly rely on relationship networks with the government tend to generate pro-social motivation that leads to persistency of entrepreneurial activities, while portfolio entrepreneurs who mainly rely on relationship networks with business partners tend to be motivated through increasing their influence in the industry which also leads to persistency of entrepreneurial activities.