Abstract: Here we present a study of bioinformatics identification of microRNA precursors in fruit crops by blasting ESTs of 32 fruit crops in NCBI using bioinformatics-based gene search and homology search method to look for miRNAs in fruit crops. A total of 110 miRNA precursors，encoding 116 unique miRNA sequences，were identified in these fruit crops. Further analysis through the miRbase database showed the 116 miRNAs belonged to 45 miRNA families，of which 7 were predicted with miRNA number more than 5，20 between 2–4，and the other 18 with only 1 miRNA. miRNAs were identified in Citrus，apple，bananas，kiwifruit and peach，and the numbers of miRNAs found in them were 28，16，13，11，and 10，respectively. The results of the alignment of 6 miRNA families showed the nucleotide sequences of the miRNAs in same family were variable，and the variation between the nucleotides of same locus could be of transversion and transition.

Key words: microRNA, bioinformatics prediction, fruit crop, EST