Six TGS sensor array used to identify four common flammable liquids and three kinds of drink with four typical feature extraction techniques and three pattern recognition methods are reported.The four feature extraction techniques involve principle component analysis（PCA）

Fisher discriminant analysis（FDA）

self-organizing mapping（SOM） and Sammon map.The result shows that the flammable species and the incombustible species can be well distinguished under each of the four feature extraction methods

while the species of samples can only be well identified under the method of FDA.The best dimension of object space depends on the feature extraction techniques

while the best pattern recognition technique has close relationship with the data sets.