Based on the statistical data of coal chemistry and coal petrology of 154samples of coal

graphite and vitrinite collected in China

this paper proposesa model of structural formula

thermal evolution process and hydrocarbon pro-ductivity of humic coal

and comes to following conclusions: 1.The typical molecular formuia of Chinese lignite with a vitrinite reflec-tance of 0.359% is C

102

H

96

O

26

. 2.Coalification can be divided into five stages. In the second stage

thebreakaway of methoxyl groups raises the curtain on the formation of hydrocarbon. 3.Under geological condition

the hydrocarbon productivity P

2

of residualcoal (water- and ash-free basis) conforms to following equation: p

2

=402e

-2.75(R

o

-0.10)

(0.30≤R

o

<

4.80) Where vitrinite reflectance R

o

is expressed as percentage

and P

2

is m

3

t

-1

. Under the condition of simulation test

the hydrocarbon potential P

3

con-forms to following equation: P

3

=598(R

o

-0.20)

0.55

e

-1.154(R

o

-0.20)

(R

o

≥0.359).