The purpose of this study was to determine the effect of Mudharabah financing on Increasing Customer Business Success at PT. Sharia BPR Haji Miskin: Customer Perspective. The type of research used in this study is associative research which is a research that aims to determine the effect or relationship between two variables. The population in this study were all customers who carried out mudharabah financing at PT. BPR Syariah Haji Miskin. The instrument of this research is a questionnaire. Then data processing is done by SPSS 22.0 with data analysis techniques using simple linear regression. As for the results of the analysis, mudharabah financing has a positive effect on the increase in customer business success at PT. BPR Syariah Haji Miskin. This can be seen from the results of the persial test t test that is the significance value of mudharabah financing is 0.023% small from the 0.05% significance value which means mudharabah financing has an effect on increasing the success of the customer's business. From the result of 20.25% mudaraba against the increase in the success of the customer's business is equal while the remaining 79.75% is influenced by other vaiable that is not examined.