Based on astrometric data from Gaia Data-Release 2 (DR2), we employ an un- supervised machine learning method to blindly search for open star clusters in the Milky Way within the Galactic latitude range of |b|<20degree. In addition to 2080known clusters, 74 new open cluster candidates are found. In this work, we present the positions, apparent radii, parallaxes, proper motions and member stars of these candidates. Meanwhile, to obtain the physical parameters of each candidate cluster, stellar isochrones are fit to the photometric data. The results show that the apparent radii and the observed proper motion dispersions of these new candidates are consistent with those of open clusters previously identified in Gaia DR2.