The invention discloses a quantitative determination device and method for coal tar in a dry distillation process of coal. The device comprises a dry distillation furnace, a pyrolyzer and an extraction cell, wherein the pyrolyzer is located at the lower part of the dry distillation furnace, a place, for arranging pulverized coal, of the pyrolyzer is a hemisphere groove; the inner end of the pyrolyzer is communicated with a gas scavenging conduit, the outer end of the pyrolyzer is connected with a guiding-out channel, the guiding-out channel is communicated with the extraction cell, the extraction cell is formed by a first extraction cell and a second extraction cell which are connected in series, the guiding-out channel is hermetically connected with the first extraction cell, the top of the first extraction cell is provided with a guide pipe communicated to the second extraction cell, and the guide pipe is hermetically connected with the second extraction cell; the outer parts of the first extraction cell and the second extraction cell are respectively provided with a cooling water interlayer through which cooling water passes, the top of the second extraction cell is provided with a gas guiding-out pipe, and the gas guiding-out pipe is provided with a gas sampling opening. The device has the advantages of ensuring the conduction of dry distillation of the coal under an oxygen free condition, avoiding an inverse suction phenomenon of extract liquor in the extraction cell, and guaranteeing the accuracy and reliability of a measured value of the content of the coal tar.