Broadly industrial applications of hydrazine cause environment pollution and damage to living organisms because of the highly toxicity of hydrazine. Therefore, monitoring hydrazine in environmental system is of great significance to human health. Herein, a new fluorescent probe PC‐N2H4 based on the corrole dye has been developed for the detection of hydrazine with excellent specificity, low limit of detection (LOD: 88 nM), and wide pH range (6‐12). Upon addition of hydrazine into the probe solution, the strong red fluorescence was “turned on” centered at 653 nm with a 127‐fold fluorescence intensity enhancement. The detection mechanism was proved by ESI‐MS, 1H NMR and DFT calculations. Importantly, the probe was utilized to fabricate a ready‐to‐use test strip to realize the visual inspection of hydrazine. Furthermore, PC‐N2H4 was successfully applied for practical detection of hydrazine in water samples with satisfactory recoveries ranging from 96.2% to 105.0%, indicating that the designed PC‐N2H4 is highly promising for hydrazine detection in an aqueous environment. In consideration of the diverse toxicological functions of hydrazine, PC‐N2H4 was also successfully used for imaging of exogenous hydrazine in HeLa cells and zebrafish.