In this study, the effect of financial reporting complexity on the accounting expertise of board members and accounting expertise, members of the audit committee and the weakness of internal control in companies listed on the Tehran Stock Exchange and Securities was investigated. The sample consisted of 100 companies from 1391 to 1398 and 800 years-company. And because the dependent variables of the hypotheses are bi-quantitative qualitative scale, the regression model of Logit model has been used. In the first hypothesis, the effect of independent variable effect, financial reporting complexity on the dependent variable, board accounting expertise has a positive and significant effect, and in the second hypothesis, the effect of independent variable, financial reporting complexity has a positive and significant effect on the dependent variable. The effect of independent variable, financial reporting complexity on dependent variable, weak internal control has a positive and significant effect and all three hypotheses were positive and accepted at 95% confidence level. The more complex the financial reporting, the greater the need for accounting expertise of the board and the audit committee, and the greater the weakness of internal control. As a result, financial complexity is greater.