Abstract: Recently, the study of petrophysics of coal reservoirs was greatly advanced. The study contents have been expanded from the analysis of the pore-fracture system of coal reservoirs in the beginning to the evaluation of coal reservoirs permeability, gas saturation and CBM pool trap, from solid properties analysis of coal reservoirs to the relationship analysis between fluid formation, reserve and pore-fracture system, and from testing the physical mechanic properties of coal to the evaluation of coal reservoirs reformbility. The testing parameters of coal reservoirs were a few at the beginning but now are plentiful for systhetical evaluation of CBM extractability and forming conditions of CBM pool. The testing techniques of coal reservoirs have been developed and the description parameters of petrophysics of coal reservoirs have been changed from qualitative at the beginning to semi-quantitative or quantitative now. The research procedures and methods of petrophysics of coal reservoirs mainly depending on the artificial outcrop analysis of coal resservoirs have been tentatively built. The detial research districts of petrophysics of coal reservoirs expanded rapidly from exploratory districts of drilling CBM wells at the beginning to the other districts now, having acquired plentiful geological informations by the observation and research of artificial coalbed outcrop underground coal mine. The situation of complement and verify each other between the parameters evaluation of CBM wells and the parameters analysis of coalbed outcrop underground coal mine have been tentatively formed. Looking ahead the developing direction of the study of petrophysics of coal reservoirs, the authors believe that the study will show great significance in CBM exploration and development.