How to evaluate commercial microloan company performance has been a real task with the wide emergence of commercial pilot microloan company in China The review of existing literature on microfinance performance will help to respond to this issue Microfinance performance is twofold, including social performance and financial performance which are indispensable, but there may be trade-offs between the two Social performance can be further divided into outreach and impact of two dimensions Outreach and financial performance can be measured directly by many indicators, also can be indirectly measured by factor analysis, DEA and other comprehensive measure These two kinds of methods both have advantages and disadvantages Impact assessment has a core problem of sample bias The result of assessment varies with the method to control sample bias