For fault diagnosis and data processing in coal mine safety production, this paper gives a kind of data processing method based on Grubbs's criterion and weighted data fusion. The method is based on intelligent detecting system and data fusion technology, it eliminates measurement data containing mistake errors by Grubbs's criterion first and then determines weight number in weighted data fusion, at last, it calculates fusion estimate to carry out fault diagnosis. The measured data verification shows that this kind of data fusion algorithm has advantages of more accurate results, simple algorithm and strong practicality, etc.