Abstract: Based on design and production practice of open-pit mines at home and abroad，cost-effective distance of automobile transport was determined，and index for cost-effective distance was put forward.The main technical parameters that affect the distance were determined by calculating：infrastructure investment，operating costs，investment effect coefficient.Time value of capital should be considered comprehensively，calculation of capital investment and business expense should be regarded as dynamic process when discussing transport distance of automobile.According to the infrastructure investment and operation cost，cost per ton of motor transport and railway transport were calculated separately under the condition of different distance.Cost diagram of motor transport and railway transport was drawn according to the calculation results.Through the diagram，the boundary point on the cost-effective distance of two kinds of modes of transportation was found (The cost-effective distance of automobile transport was 1.85 km).The conclusions are that cost-effective transport distance of automobile，which varies with different transport conditions，is not a fixed value; cost-effective transport distance of automobile is correlated negatively with volume，positively with mining depth and vehicle capacity.Meanwhile，it is closely related to type of mines.

Key words: Open-pit mine, Automobile transportation, Railway transportation, Cost-effective distance