Using the ongoing Zwicky Transient Facility (ZTF) survey, we investigated the intra-night optical variability (INOV) of intermediate-mass black hole candidates (IMBHs). Among 953 selected IMBH candidates with broad Ha component and ZTF photometry monitoring, we focus on 76 candidates with logMBH<6, r<19.0 and 203 sessions of intra-night data, each epoch including more than 20 data points with at least 3 hours. By excluding the influence of observational seeing effect and host galaxy light diluting the subtle AGN variability, we set strict constraints on the seeing variation of the intra-night session and obtained each session’s light curve by carrying out the aperture photometry on the ZTF differential images. We find that ∼10% of the sessions show INOV based on four statistical parameters describing the INOV variability. The possible nature is briefly discussed. The candidates provide robust candidates for future IMBH reverberation mapping project, enhancing the possibility of detecting variability and lag in future IMBH reverberation campaigns.