The presence of interstellar molecules would provide the important information for the revolution of interstellar gas and stars.By mimicking the environment of interstellar space with low molecular density in the laboratory, the potential astronomical molecules will be produced on line via the collision under the DC discharge. With pulse jet-Fourier transform microwavespectroscopic technique, the high resolution rotational spectra of potential interstellar molecules will be investigated. The typical pattern of their rotational spectra will be identified. The obtained precise spectroscopic and structural parameters, and the deduced mechanics upon formation are essential to their observation in the interstellar space.