A high-throughput, selective, and sensitive colorimetric method has been developed for probing free microRNAs (miRNAs) in blood based on a “self-cleaning” functionalized microarray newly fabricated. Glass substrates were first masked with a hydrophobic silane layer of hexadecyltrimethoxysilane (HDS) and then dotted with hydrophilic aminopropyltriethoxysilane (APS) embedded with nano-scaled ZnO, resulting in HDS-ZnO-APS dot microarray with highly dense ZnO-APS testing dots and depressed crossing contamination of sample droplets by the lotus-like “self-cleaning” effects of hydrophobic HDS substrate. Furthermore, ssDNA capture probes with hemin-binding sequences were covalently anchored on the amine-derivatized ZnO-APS testing dots. After miRNA target hybridization, exonuclease I was introduced to specifically digest the ssDNA probes unhybridized. Furthermore, hemin was added to form the hemin-G-quadruplex DNAzyme to achieve the ATP-enhanced catalytic amplification of visible coloration signals. Wild miRNA targets in blood could be detected in the concentration range from 0.20pM to 1.50nM, with the detection limit of 0.080pM. Single-base mutation miRNAs could also be accurately identified and quantified for profiling miRNA expression pattern. Markedly different from the common microarray assays by way of sandwiched detections, such a microarray-based colorimetric method could be tailored for quantifying short-chain miRNAs of low levels in blood.