The research is to sample the data of CPA firm service industry report of Taiwan district from 1997 to 2005, and the sample period is divided into 3 groups, 1997 to 2001, 2002 to 2005 and 1997 to 2005. In addition, the samples are divided into whole, large, middle and small CPA firm, and implement the description statistic analysis, relativity coefficient and regression analysis. The results are as follows: I. The small CPA firms The firm’ main business is to serve client, and the operating result is probably relative to audit service revenue and non-audit service revenue due to lower personnel cost. II. The middle CPA firms It is easier to expand the tax affair business and management consultant business in distribution of job and professional because the CPA member is more than 1 people so that the operating result is positively relative to non-audit service revenue due to the stable growth of non-audit service revenue. III. The large CPA firms The CPA firms whose revenue comes from open publication attestation invest a large amount of manpower and materials in meeting the implementation of new financial accounting statement (FAS) and the enormous revision of many numbers of FAS so that the operating result is positively relative to audit service revenue due to the growth of audit service revenue. IV. The whole CPA firms The operating result of Group II is positively relative to audit service revenue, non-audit service revenue, the ratio of CPAs to employees, market share, salary expense, and risk level. It is probable that the revolution of CPA exam system decrease the entry level of CAP industry.