A laboratory simulation experiment to study the interaction between a cometary plasma and the solar wind has been performed using the UCR-Tl space simulation facility (dia. 1.3m, length llm). Intense plasma flow simulating the solar wind interacts with another light-emitting plasma composed of Ba, Sr, and/or C by a plasma emitter which simulates a cometary coma. The purposes of this experiment are to investigate how the solar wind parameters contribute to the formation of the cometary ion tail and to determine the magnetic field structure of a comet. In order to estimate the solar wind parameters by ground-based observations of actual comets, knowledges of such relationships are essential. Our experimental results show that the interplanetary magnetic field (IMF) of the solar wind is very important in forming the cometary tail. The origin of the so-called "tail rays" and the magnetic field structure in a simulated cometary ion tail are introduced.