Heating the oil shale by current underground to accomplish in-situ transformation process，is a viable direction． The electrical properties of oil shale under different temperatures，especially the resistance，become important． Charging oil shale underground to heat oil shale till kerogen's decomposition temperature，then crude oil and other gases can be generated． The resistance of the oil shale samples was measured by Direct Current ( DC) quadripole method to find out the variation rules of resistance value． In the experiments，oil shale presented its semiconductor property． When heated till 350℃-450℃，its resistance changed greatly，optional for heating and cracking． The porosity，oil content，media and composition affected the resistance largely．