One  of  the  most  important  characteristics  of corporation is  distinction between  ownership  and  management.  On this basis, manager exclusively available to access to apart of information   and   he/she is   responsible to preparing and transferring financial information. Because of  such  authority and  other  characteristics  such  as  characteristic  of  accounting  , because of  accruals (difference  between  cash  basis  income and   accrual  basis  income)  and   incentives  such  as  bonus incentive  , income smoothing, desert  of regulation, manager available   and  willing   to  manipulate   information   (income management),   specially  financial  information,  in  direct  of his/her benefit and in contrast with benefit of other groups. This   object, in this research and in form of four hypotheses, in connection of management bonus, prediction of bonus and income, income smoothing and monitoring of regulation of pricing is tested. These hypotheses are analyzed by regression analyzing and Wilcoxon test. On basis of research result and considering of limit in available to financial information of some statistic popular corporations, managers are willing to manage the income in periods that corporation  has loss or income, in order to increase the bonus; and  in profitability  periods, in order to smooth the income.