There exists a suite of complex porphyries in the Yao'an Pb-Ag deposit, such as syenite porphyry, trachyte, pseudoleucite porphyry, and phenocryst-bearing syenite aplite, with the syenite porphyry being the host rock. Through an integrated study of the spatial distribution and petrological and mineralogical characteristics of pseudoleucite porphyry through field geological survey, microscopic identification, electron microprobe analysis and X ray diffraction analysis, the following results have been obtained:① Pseudoleucite porphyry is outcropped in the periphery of syenite porphyritic volcanic breccia in the forms of veins, breccia or small apophyses and is mainly distributed in the southwest of breccia-type orebodies and the northeast of F₄ fault. Pseudoleucite porphyry is associated with breccia pipe and peripheral fault in space; ② Pseudoleucite has two generations. The early pseudoleucite phenocryst is in the grayish green round form rich in Al, whereas the late pseudoleucite phenocryst, which exhibits high Si and Na, is grayish white tetragonal trisoctahedron phenocryst. Both of them have been replaced by altered minerals such as potash feldspar, kaolinite, and quartz; ③ Pseudoleucite porphyry was formed in an intraplate extensional environment after the collision between India continent and Eurasia continent; ④ Pseudoleucite porphyry was formed later than trachyte, syenite porphyry and earlier than phenocryst-bearing syenite aplite. It had no direct genetic connection with galena mineralization.