In order to study the effects of the hydrogen agent and metal catalysts on in-situ combustion development，effect of the formic acid，ferrous（nickel）-base ions solution on improving the oxygen utilization rate and combustion efficiency was investigated during heavy oil flooding；effect of adding the ferrous ion solution on thin oil combustion stability was also probed . Experimental results showed that，compared to the basic heavy oil fire flooding experiment，after adding 0.3% formic acid and 0.05% ferrous ion solution into the simulated oil sand，the combustion stability was enhanced and the CO₂，CO content in the exhausted gas increased while the O₂ content decreased significantly，the O2 utilization ratio increased by 8.27%，the combustion front was increased by 27℃ and the oil recovery was enhanced by 7.33%. Compared to the thin oil fire flooding base experiment，the addition of 0.05% ferrous ion solution made fuel concentration increased，which ensured the sustainable combustion on the thin oil fire flooding experiment.