This invention relates to an analytical instrument field, specifically an instrument for pharmaceutical micromolecular and biological macromolecular ion generation. By this invention, through a hollow capillary emission needle and an emission needle bracket, the emission needle bracket forms a forward moving laminar flow gas surrounding the emission needles, eliminating the capillary counter-flow effect outside the capillary for liquid flowing out of the hollow capillary emission needle and pushing liquid forward; and vacuum lead-in capillary whose entrance is a specially designed arc mechanism, makes zero air flow speed in any direction, and the entrance happens to be the exit of the hollow capillary emission needle so as to ensure steady Taylor cone on the tip edge and ultimately obtains steady ion flow within a large flow range. This invention has advantages of steady ion emission and high ion transmission efficiency, and can be widely applied in the ion source preparation.