本文利用现有旋涡星系中性氢密度分布和速度分布模型，来产生星系中性氢的21cm谱线模拟观测数据。首先，利用文献中的结论，结合星系的发光物质质量和色指数，本文给出了旋涡星系中性氢密度的径向分布，在星系外区，中性氢面密度按指数规律下降；在星系内区，随着半径的增大，中性氢面密度先升高后降低。其次，旋涡星系的速度分布，即它的旋转曲线，理论上由该星系各物质组分的分布决定，本文根据其它文献中的结果，根据该星系的发光物质质量确定其旋转曲线。最后，利用以上结果，假定中性氢21cm谱线轮廓为高斯轮廓，结合中性氢质量和21cm流量的关系，本文给出了单个旋涡星系21cm谱线模拟数据，数据形式为数据立方体（data cube）。

This paper gives a mock HI 21cm data cube for a given galaxy using its HI radial distribution and rotation curve. The HI radial profile is derived from galaxy’s stellar mass and color index. The profile is universal and exponential decreasing at the outer region of the galaxy when the radius is scaled by R1, the radius at which the HI density is 1 solar mass per parsec square. At the inner region, with the increase of radius, the profile first increase and then decrease. Theoretically, the rotation curve should be derived from matter distribution of different types of matter. In this paper, a rotation curve is assigned to the galaxy according to its stellar mass. Finally, assuming a Gaussian line profile, combining the above work and the relation between HI mass and 21cm flux, a HI 21cm mock data cube is generated.