Using homemade pine fuel rods as the experimental object, the influence of temperature on dolomite catalytic steam gasification was studied. The results showed that the calcined dolomite can cause long carbon chain cracked, which was conducive to the production of radical hydrogen ion, and helpful to generate hydrogen. Compared with no added catalyst, the volume fraction of H2 was increased from 31.91% to 38.82% at 750℃, increased from 32.32% to 40.11% at 800℃ and increased from 46.01% to 48.16% at 850℃. When temperature was less than 850℃, the volume fraction of CO was reduced due to that the oxidation reaction of carbon monoxide was more dominant than other gasification reaction, and calcined dolomite was easy to absorb CO2. When the gasification temperature was more than 850℃, because the rate of dolomite catalytic cracking of tar was increased, and the decomposition of carbonates was strengthened with increase of temperature, the rate of increase of CO2 volume fraction was higher than the increase of H2 and CO volume fractions, which caused the reduction of H2 and CO volume fractions (compared with no catalyst added), but the volume fraction of CO was increased. Dolomite catalyst can promote the gradual fracture of the carbon chain of hydrocarbons and make them to be small molecule, such as H2, CO2, CO, etc., and this process was severer with temperature increasing. Dolomite was beneficial to the carbon chain scission reaction, ring opening reaction, decarboxylation reaction, decarboxylation and triple bond cleavage reactions of aromatic hydrocarbons and aliphatic. When temperature was over 850℃, hydrocarbon chain scission and ring opening reaction with the dolomite catalyzed were increased, making its end chain hydroxylation and gradually formed with terminal methyl dehydration condensation ether, and that rate was higher than the rate of oxidation and removal of hydroxyl and ether chains with temperature increasing. Because under the condition of steam atmosphere, the removal rate of carboxyl group was increased with the increase of temperature, and it was faster than the rate of oxidation of hydroxyl and ether chains to produce carboxyl groups, which caused the integral area of the characteristic peak of carboxyl group increased first and then decreased.