Private placement is one of important equity financing instruments of public companies. There are many foreign studies on private placements including pricing discounts, placement motivation, short term stock price reaction and long-run performance of public companies which form a series of theories and hypotheses, the domestic academic studies mainly focus on announcement effect of private placement, pricing discount of private placement, the benefit change situation of stakeholders in the process of private placement and so on. The existed researches more emphasize empirical studies and are inadequate in the aspect of the discrepancy between different states and different regions, the research of domestic scholars is not systematic and complete in the perspective of public companies’ private placement preference, market reaction and its influencing factors.