Abstract: An automatic screening system for maize haploid kernel identification based on oil xenia effect and nuclear magnetic resonance (NMR) is developed to meet the demand of large-scale application in maize haploid breeding and research. The screening system was comprised of a seed feeding module, a measurement module of oil content and a screening module. The results show that the mean accuracy of this screening system reaches 92.3%. Even with the shorter signal acquisition time, the accuracy does not show a significant decline. The automatic screening system can be used in practical application in rapid selection of maize haploid seeds and can also be used to separate the samples of different oil contents.