This paper introduces a random measurement analysis of, lung function measurement values with two different apparatus. in 41 patients. It shows that the differences are not statistically significant (P>0.05) between two apparatus measurement values except DLCO, FEF25, FEF75 in the group of normal ventilation, FVC in the group of abnormal ventilation. The two groups are both correlated closely (r> 0.9) except MMF(r=0.7725, RV r=0.808) in the normal group of ventilation, and FEF75 (r=0.58) in the abnormal group of ventilation (p<0.001). The two apparatus with different measuring theories have a good correlation.