Electronic devices that can accurately record and monitor human respiration in real-time are of great interest for researchers. Ultrafast-response ionogel humidity sensors that can follow the human respiration were realized by an in-situ vinyl-thiol click reaction in this work. Polyacrylic acid (PAA) was utilized both as the template to construct porous films and for preparing humidity sensing component. The obtained optimal sensor owns a rapid response to humidity change (response and recovery time is 1.2 s and 0.6 s, respectively) and a small humidity hysteresis (∼2.2% RH). The water adsorption capability and sensing mechanism were investigated systematically. The ionogel humidity sensor with good stability and repeatability was applied in breath monitoring, which has a great potential application in diagnostic breath analysis.