Tidal disruption event (TDE) occurs when a star approaches too close to a supermassive black hole (SMBH). If the circumnuclear medium is dusty, the original TDE emission (soft X-ray, UV, optical) will be reprocessed into infrared (IR) band like an echo. Therefore, the IR echoes provide us a unique opportunity to study the dust environment around SMBHs down to subparsec scale, which is otherwise extremely difficult to probe. On the other hand, they can serve as an effective means to unveil obscured TDEs, which might be overlooked by optical/X-ray surveys. In this talk, I will first introduce the IR echoes detected in TDEs and the dust properties learned from them. Then I will show our ongoing project on Mid-Infrared Outburst in Nearby Galaxies (MIRONG), which was proposed out to uncover TDEs in dusty environment. I will share some interesting results from the MIRONG project and highlight why IR echo is crucial for understanding TDEs thoroughly.