In this study, the relationship between auditor tenure and the ability to forecast earnings About 117 firms listed in Tehran Stock Exchange for the financial years 1384 to 1390 are examined. Given the importance of predicting future profits, investors are always looking for predicting the criterion, Therefore, the profits and operating cash flow as a measure to predict future profits are concerned. Firstly, the relationship between auditor tenure and earnings predictive ability was tested the results of the regression analysis showed a direct relationship between auditor tenure and earnings are predictive ability. The relationship between auditor tenure and earnings forecast error, the company's growth and earnings per share growth was examined, The results indicate that there is an inverse relation between auditor tenure and earnings forecast error and direct relationship between auditor tenure and earnings per share is the company's growth and development.