本文以中國擇日行為之理論為基礎，以我國會計師產業為對象，探討會計師事務所在不同的開業時間，其利潤績效的差異性。主要研究發現為，首先，我國會計師事務所的創立者，似乎不太會選在吉年來開業，多數甚至均選在不吉月來開業。其次，在吉祥年度成立之事務所，其利潤率最高，然而在吉祥月份成立之事務所其利潤績效並未較非吉祥月份設立者為佳。第三，小規模事務所的在吉年設立時，其利潤率相對相高，然而在吉月設立時，則否。最後，單獨開業事務所在吉年設立者，其利潤率相對相高，然而在吉月設立時，其利潤率反而相對較低。 本文之研究結果或許可以提供我國會計師產業的決策階層進行開業時間選擇的參酌。 The purpose of this study, based on Chinese calendaring and Opening time, is to explicate the profitable distinction among accounting firms. First of all, according to the research, it appears that the owners of accounting firms mostly started business without calendaring to specify in felicitous lunar year as the opening time; furthermore, most started business on ominous month. Secondly, those which started their business in felicitous lunar year profited well; however, those which started business on felicitous lunar month profited no better than those at random did. Thirdly, tiny accounting firms which started business in felicitous lunar year profited well; on the contrary, those on felicitous lunar month profited badly. The last, sole firms which started in felicitous lunar year profited well; however, those which started business on felicitous lunar month profited badly to the contrary. The results of this research probably could provide significant reference for those who manage accounting firms to decide the proper opening time.