The invention discloses a novel mini pump capable of self-priming, and effectively settles the problems of periodical fluctuation, unstable flow, failure to self-prim, inapplicability to gas working substances, and so on. With the pump, the output flow is more stable and capable of continuous adjusting and complete self-priming, and no sample injection is required. The pump is not only applicable to liquid working substances, but also applicable to gas working substances, so the using scope of the mini pump is enlarged and the usable life and working stability of the mini pump is increased. The novel mini pump is simple in the structure. The pump comprises a lower pump plate, an upper pump plate, a drive, a pump chamber, a valve seat, a first cone diffusion pipe, a cone contraction pipe, and a second cone diffusion pipe, and is provided with the advantages of the quick response, the broad drive frequency, the strong controllability, the low power consumption, the long usable life, the small dimension, the simple manufacture technique, the low cost, and so on. In addition, the invention can be manufactured by using the technique of micro-processing and materials compatible with the micro mechanical technology, and can be integrated easily with other micro tests, micro-controlled elements and so on. The invention is suitable for mass production and is provided with a very wide application prospect.