The effects of CO2 and H2O on solution loss reaction of coke were studied in the temperature range of 950~1200℃ with self-made gas-solid reacting apparatus. The results showed that the gasification rate of coke reacting with H2O was about 2~7 times of that with CO2. The difference of gasification rate was narrow with rising of the temperature. The reaction process was controlled obviously by interfacial reaction, it could be described by the unreacted core shrinking mode. The activation energy of coke reacting with CO2 and H2O was 165.481 and 82.25 kJ/mol, respectively. The amount of solution loss decreased from the outside to the inside of coke particles with rising of the temperature. Compared with the reaction of coke with CO2, that with H2O occurred much more on the surface of coke. The pores in coke formed differently in its different parts. After reaction with CO2 and H2O, the proportion of pores with the sizes over 10 mm in coke increased 66.98% and 94.01% in the edge part of a coke particle, but that decreased 21.22% and 3.30% in the central part.