The softening and melting of cohesive tar-rich coal caused by heating may lead to wellbore blockage and formation disturbance,which is an important factor to be considered for in-situ pyrolysis. In this paper, the pyrolysis of cohesive tar-rich coal at 300-700 ℃was conducted to investigate the oil and gas precipitation rules and their composition properties, and the evolution characteristics of physical properties of semi-coke and its indicative significance for in-situ pyrolysis were analyzed. The results shows that the tar yield reachesthe maximum value of 7.75% at 500 ℃ , and the content of light components (boiling point lower than 300 ℃ ) of the derived tar is thehighest (32.2%). The tar components chang significantly at 400-500 ℃ , and the content of phenols increases while that of aromatics decreases. The softening temperature and curing temperature of the coal sample are 389 and 455 ℃ respectively. Consequently, the macroporosity of semi-coke increases from less than 10% to about 50% at ≥400 ℃ , while the micro-pore structure is more developed only atthe high temperature stage of 600-700 ℃ . The thermal conductivity of semi-coke decreases first and then increases with temperature, andreaches a minimum value of 0.06 W/ (m·℃ ) at 400 ℃ . In-situ pyrolysis of cohesive tar-rich coal may be confronted with potentialproblems such as channel blockage, volatile precipitation obstruction and slow thermal conductivity of coal seam. These problems are expected to be solved by using fracturing proppant with viscosity breaking effect or applying near critical water in-situ conversion technology.