球状星团作为星系中一种年老的简单星族系统，对星系结构、星系演化历史的研究 起着至关重要的作用，而寻找河外星系中的球状星团，是研究星系中球状星团系统性质 的基础。GAIA 数据的出现，为清除视场内的前景污染提供了更多选择。本文以 GAIA 数 据为基础，采用 Voggel、Hughes 等人提出的方法，以 NSC DR2 和 DESI Legacy Imaging Surveys DR10 提供的多波段测光数据为辅助，筛选了四个近邻早型星系 (NGC3115、 NGC3377、NGC3412 和 NGC5128) 半径∼ 200 kpc天区范围内所有的 GAIA 源，得到了一 批球状星团候选体，并对得到的星团候选体的统计性质进行了初步研究。本文还首次发 现，利用(g-r) vs. (r-z)双色图可以分离恒星、星团与星系三类不同的天体。

Globular cluster (GC) systems, tracing the old stellar population in galaxies, play a significant role in the study of the structure and evolution history of galaxies. It has been challenging to select photometric candidates of extragalactic globular clusters with high purity and completeness. The appearance of Gaia provides more options for removing foreground star contaminants in the field of view. Adopting a new method proposed by Voggel, Hughes et al., we present a catalog of globular cluster candidates in four nearby early-type galaxies (NGC 3115, NGC 3377, NGC 3412 and NGC 5128) out to a projected radius of ∼ 200 kpc based on Gaia DR3, taking NSC DR2 and DESI Legacy Imaging Surveys DR10 as auxiliary. We present preliminary results of the spatial distribution, color distribution and luminosity distribution of the GC candidates we have found. In addition, we find for the first time that the (g-r) vs. (r-z) color- color diagram can be used to separate galaxies from globular clusters and stars.