A rapid, simple method was developed for the determination of R-70 self-heating rate of coal. The coal samples were tested under adiabatic and programmable temperature conditions. separately. It indicates that it is a linear relationship between the differential value of oxygen concentration at 70 degrees C under a programmable heating condition (Delta C-O2.70) and the adiabatic R-70 self-heating rate. This linear relationship can be described by a fitted trendline equation R-70 = 0.68504 Delta C-O2.70 + 0.12098. So the R-70 can be determined by testing the value of Delta C-O2.70. For most coals, the testing processes of Delta C-O2.70 need a time less than 1.5 h. A new evaluation method for the propensity of coal to spontaneous combustion was also proposed from previous R70 method. Based on the value of Delta C-O2.70, a coal with a Delta C-O2.70 value below 0.55% is considered to be low risk. 0.55-1% medium risk, higher than 1% high risk. The study will be helpful for more widely and convenient use of R-70 self-heating rate. (C) 2013 Elsevier B.V. All rights reserved.