Aimed at the technical difficulty of low electric conductivity of novel organic semiconductor,a kind of laminated microstructure on porous upper electrode was brought forward.A gas sensitive film was formed using vacuum deposition,then,a gas sensor was developed by MEMS micro-fabrication.According to the equivalent circuit and the technologic boundary condition,the output conductance of the sensor has increased by 1 000 times derived by a conductance formula,which solves the signal gathering problem of organic semiconductor.SEM microcosmic pattern indicates that the best condition is the evaporating electric current of 100～120 A,and evaporating time of 8～12 s.On that condition,the surface of gas sensitive film is covered with activated granules inosculated by the secondary chemical reaction,like rice grain in uniform distribution and ordered holes.The testing result indicates that vitriol doped CuPc_xPANI_1-x with proportionality coefficient of 0.15～0.35 has the best sensitivity to SO₂.The CuPc_0.35PANI_0.65 is selected in order to reduce the interference of H₂S.When heating voltage V_H is 1～2.5 V,sensitivity and responsive restorability will be enhanced and responsive time is 30 s.The output characteristic of sensor is single linear logarithmic,the detecting range is 0～200×10^-6.Through stability examination for six months,output impedance shift and sensitivity are less than or equal to ±5% and 10%,respectively.