中文摘要：

基于上市公司中期财务报告审计，本文对公司自愿审计行为进行了考察。研究发现，股权结构和董事会等治理机制显著影响了公司自愿审计的动机。具体的，第一大股东持股比例与中报审计间呈先减后增的非线性关系；由于大股东间的“合谋”，股权制衡类公司更不会进行中期财务报告审计；随着董事会独立性的提高，公司审计中报的动机增强；最后，董事会规模适中的公司具有较优的治理效率，更易进行中期财务报告审计。就经济后果而言，上市公司自愿实施的中期财务报告审计降低了公司盈余管理的水平，提高了公司盈利反应系数。

英文摘要：

One of the earliest steps in recognition of auditing as an institutional arrangement occurred in England with the passage of the Company Act of 1862, and another one occurred in US with the enacting of Federal Securities Law. However, according to Watts and Zimmerman （1983）, the appearance of audits is more recent and is more nongovernmental. Then, what causes voluntary audit to occur？ What drives corporate to voluntarily be audited？ And how can voluntary audit influence accounting information disclosure. These questions are not unimportant but unnoticed. We use interim reports of China listed companies to investi- gate the incentives and consequences of voluntary audit. We find that ownership structure and corporate board are all related to incentives of vol- untary audit. Specifically, large shareholder ownership is U-shape correlated with interim re- ports audit; firms with shareholder mutual~restriction are less likely to have interim reports audited due to the collusion of large shareholders; if the board has relatively more independent directors, the firm is more inclined to voluntarily audit; finally, firms with a modest size board are more engaged in voluntary audit. For the economic consequence, voluntary auditing of interim reports reduces the level of firm＇s earning management and generates higher ERC.