The approximately 21 nucleotide microRNAs (miRNAs) are one type of well-defined small RNA species, and they play critical roles in various biological processes in organisms. In plants, most miRNAs exert repressive regulation on their targets through cleavage, and a number of miRNA-target pairs have been validated either by modified 5' RACE (rapid amplification of cDNA ends), or by newly developed high-throughput strategies. All these data have greatly advanced our understanding of the regulatory roles of plant miRNAs. On the other hand, deep insights into miRNA precursor processing, and miRNA- or miRNA*-mediated self-regulation of their host precursors could be gained from high-throughput degradome sequencing data, based on the general framework of miRNA generation in plants. Here, the focus is on the recent research progress on this issue, and several interesting points were raised.