A typical case of Didi Chuxing was selected, and based on psychological contract theory, a Chinese management rooted research paradigm was adopted to explore the factors influencing flexible employment labor relations on modern sharing economy platforms and construct a model of the influencing factors. The study finds that flexible employment labor relations are influenced by both internal and external factors. In terms of external factors, the macro environment, consumer attitudes, and consumer behaviors indirectly regulate flexible employment labor relations by influencing the management of the platform and labor gains. In terms of internal factors, the psychological contract between the modern sharing economy platform and the service provider directly influences the flexible employment relationship. Compliance with transactional contracts is the “foundation stone” for the normal development of flexible employment relations. The observance of relationship-based contracts is the “lubricant” for the positive development of flexible employment relations. Compliance with developmental contracts is a long-acting medicine for the harmonious development of flexible labor relations. This study can provide theoretical and practical guidance for the governance of platform-based flexible employment labor relations.