Plant microRNA (miRNA) is a group of endogenous non-coding RNAs that participate in regulating gene expression during the processes of plant growth, development and metabolism. Recent studies indicated that miRNAs play important roles in plant adaptation to low phosphorus stress by regulating phosphorus absorption and utilization. This review summarizes the molecular mechanisms of phosphorus absorption and transport by plants, and introduces the transcriptional patterns of miRNAs under low phosphorus stress. Especially, this focuses on plant miRNAs responding to low phosphorus stress, including structure modification of root system, improvement of the efficiency of phosphorus transport and reuse, as well as anthocyanin and anti-oxidant biosynthesis. It is expected to provide insights for unlocking the molecular mechanisms of plant responses to low phosphorus stress and improving the efficiency of plant phosphorus absorption.