Organic ultraviolet photodetector (OUV-PD) has been specially concer ned due to the advantages of wide range of material selection,low cost,flexibility and large -area manufacturing．The OUV-PD with structure of ITO/m-MTDATA (30nm)/m-MTDATA:BAl q(40-60nm,1∶1) /BAlq(nm 40)/LiF(1nm)/Al(100nm) was prepared.The effects of Liq,TPBi,Bphe n and Zn(4-MeBTZ)_2as cathode buffer layers on the performance of OUV-PD are studied.The experim ental results show that the photoresponse of OUV-PD is closely related to the thickness and el ectron mobility of cathode buffer layer.Under an illumination of 365nm UV light with power of 1.05mW/cm²,the maximum values of response are 218mA/W,247mA/W,305mA/W and 283mA/W,respec tively.