Piwi-interacting RNA (piRNA) was discovered in 2006 and is a class of small non-coding RNAs (sncRNAs) which interaction with the PIWI family. piRNAs is the largest class of small non-coding RNA molecules expressed in animal cells.They are emerging as key factors in the regulation of various diseases. Single nucleotide polymorphisms (SNPs) are widely distributed variations which are associated with diseases and have rich information. In order to supply a comprehensive source about piRNA related SNPs, we developed a public database piRSNP. We comprehensively identified SNPs on human piRNAs by mapping. In addition, SNPs on cancer-related piRNAs and their flanks are investigated. Impacts of them in cancer-related piRNAs on piRNA-mRNA interactions are analyzed.