Non Performing Financing (NPF) be one measure of the performance of banks functions. Because of the high NPF is an indicator of the failure of the bank in managing the business and affect the onset of the problem of liquidity, solvency, and profitability. In addition, bank profits will decline due to decreased revenue sources, namely of financing and on the other hand should be set aside as a reserve fund in accordance of financing collectability. This research aims to explain the influence of internal variables banks in the form of financial ratios consisting of Capital Adequacy Ratio (CAR), Financing to Deposit Ratio (FDR), Operating Expenses Operating Income (ROA), and the size of the Bank to fluctuations net Non Performing Financing (NPF) Syariah Bank in Indonesia in the period of 2010 January to 2015 in June. The research data used are secondary data obtained from Bank Indonesia and the Financial Services Authority. Methods of data analysis using the Error Correction Model (ECM). The results showed that in the long term variable CAR and FDR did not affect the NPF, while variable BOPO and Bank Size positive and significant impact on NPF. In the short term the only variable FDR showed that positive and significant impact on the NPF, while variable CAR, ROA, and the size of the Bank does not affect the NPF. To lose and keep the NPF ratio is not too high, the banks should improve management of bank financing in analyzing the customers who will receive the funds provided and observe the behavior of the customer's business after the borrowing of funds.