Abstract: This paper presents the design of the vacuum system and the sampling system for the time-of-flight mass spectrometer (TOFMS) used for space exploration, and establishes the ground experimental system for the TOFMS prototype. In order to be used in the space exploration mode and the ground experiment mode, two sets of the vacuum system are designed. A theoretical analysis model of gas sampling is established. According to the model, and with theoretical analysis and calculation, some results are obtained from the ground experiments, including the vacuum degree of the mass spectrometry chamber, the Voltage-Amu mass spectrogram of the air, the Voltage-Amu mass spectrogram of Kr sample and its sampling time. The results show that the design of the vacuum system and the sampling system is reasonable and can meet the requirements of the experiments, and the theoretical analysis model can be used to guide the experiments.