Keywords: 
• Markov Chain /
• micro-sequence of coal seam /
• coal reservoir /
• pore surface area /

Abstract: Based on the principle and method of M arkov Chain, the methematic model w as established in o rder to describe the forming process and the micro-sequence of coal seam, The follow ing conclusions have been draw n: (1) The test values are far more greater than the ci tical points at different confidence levels, the microlithoty pe sequence of coal seam is fi t to the Markov Process.(2)The statistic direction of the microlithoty pe sequence w ithin each sublayer has hardly effiect on the analy sis result.(3)The thickness of the main states will be in- creased and that of the secondary decreased during the simulation of microlithoty pe sequence.This thickness change will make the simulating microlithotype sequence simple and clear.(4)The location of each microli tho- type fo r a case w as defined through the model fitting to coal structure, so the heterogeneous characteristics of coalbed methance(CBM)w ere predicated.(5) The advantageous gas-storaging location in the coal seam can be forecasted by combining the anslysis of the specific surface area of pore and the gas-storaging capaci ties of the different macerals w ith the microli thotype sequence of coal seam.So a new insight to evaluation on geologi- cal conditions of CBM development has been given.