The Matlab high-performance language for technical computing integrates computation,visualization,and programming in an easy-to-use environment where problems and solutions are expressed in familiar mathematical notation.It allows you to solve many technical computing problems,especially those with matrix and vector formulations,in a fraction of the time it would take to write a program in a scalar noninteractive language.The Matlab had a important application in seismic studies,such as,the ZMAP software used for scanning b value and application of Matlab software on intensity rapid report of Tianjin strong mation network.Authors developed the analysis software of the subsurface fluid based on Matlab,which combined with the function of some other geochemical software.This paper mainly discussed the water quality analysis by means of the software,and studied on the spring water in the north margin of western QinLing fault zone and comparatively analyzed the chemical composition characteristics of hot spring water in Wushan,Jiezi and Qingshui.In this paper,the types,water qualities,supply sources,the state of water-rock reaction and circulation depth of the water were discussed.And the paper analyzed that the circulation depth of hot spring water impacted on the seismicity of fault zone.In this paper,we drew the linear correlation diagram ofδDandδ18 O of hot spring water samples in the north margin of western Qinling fault zone.By the composition analysis of Hydrogen and Oxygen isotopes,it was showed that the supply sources of the water in three springs are precipitation and the isotope exchange effects caused positive shift of the 18 O.Based on Rectangle hydrochemical diagram,it was the results that the hot spring water in Wushan and Jiezi was belonged to Na-HCO3·SO4·Cl and carbonated water of hydrochemical type,but the water in the Qingshui hot spring was belonged to Na-SO4·Cl and sulfuric water of hydrochemical type.In overall,three hot springs was the type of low salinity water.Because the different reactions were taken place between water and surrounding rock during the water cycle,chemical composition type of the spring water in Qingshui distinguish the Wushan and Jiezi.We came to some conclusions by mean of comparing depth of the spring water cycle with seismic activity of fault zone.The hot spring water with shallow depth of the water cycle,in Wushan and Jiezi,and the seismic activity was frequent in the local fault.But,the water-circulating depth of the spring water in the Qingshui was deep and the seismic activity of local faults was weak.This paper was showed that it were a correlation between the depth and seismic activity.The water during depth circulation had a strong weakening effect on its surrounding-rock on the fracture.The deep fluid provided with greater pore-pressure could reduce the effective positive pressure of fracture surface.The water with deeper cycle had a the higher level of weakening effect on fracture and caused the lower strength of fault zone.It affected the fault activity.All in all,this paper was showed that the geochemical characteristics of the spring water were differences between Qingshui and Wushanand Jiezi.In addition,whether it is a correlation with the size of fault activity will be required more in-depth study.