MicroRNAs (miRNAs) are non-coding RNAs, which regulate gene expression by promoting degradation or repressing translation of targeted transcripts. Current researches indicate that microRNAs play essential roles in heart development, but their regulating mechanisms are still elusive. Using computational methods, we analysed microRNAs associated pathways in mouse heart development and found that 24 pathways were enriched with target genes of microRNAs. Some of these pathways are reported important in heart development, while others are associated with cancer. The computational results could be used to guide experimental design for the further understanding of the microRNAs function in heart development.