In Caenorhabditis elegans, the expression of all piRNAs, small of miRNAs were influenced by the mutation of prg-1. Especially, some ncRNA-like, a kinds of small RNA, were found in C. elegans. The ncRNA-like had the similar sequence with piRNAs or miRNAs. The results of the analysis in the gene sites between the ncRNA-like and piRNAs or between ncRNA-like and miRNAs, showed that ncRNA-like had the same gene sites with piRNAs or miRNAs. All of these showed that the ncRNA-like were a kind of small RNA and may be processed from the RNA precursor same to piRNAs or miRNAs.