The paper gave definition to the efficiency of family farms firstly, then we used Farrell's production efficiency measurements as reference, to make a probe on the premise assumptions, the realization condition and the theoretical model to the measurement of family farm's efficiency, and then we constructed a family farm efficiency evaluation model based on nonparametric DEA method. On this base, we made a confirmatory analysis by using the data of 10 family farms in Gannan. It showed that, the model can give identifications on whether a family farm is completely vrste, crste and scale efficient. Finally, we showed the implications and suggestions on efficiency promoting of family farms.