This paper detects whether seasoned equity offering (SEO) firms manage earnings in the year before a planed issue and the inducement factors of earning management. We select 106 SEO firms during 1999 to 2001 as test sample and another 106 non-SEO firms matched at calendar year, Industry and cash from operation as control sample. Using 3 three test methods, we find that firms contemplating SEO in the following year do manage earnings particularly when their relative performances are poor. And we also find firm size, CFOs and debt ratios are important inducement factors of earning management.