Onsite ultrasensitive identification of the airborne or deposited perchlorate particulates is crucial for homeland security, forensic analysis, and environment monitoring. However, few of the currently developed luminescent sensor focus on the direct and ultratrace detection of its solid particulates as the low level of analyte and the difficulty in exhaustive collection of the trace sample. Here, a general design strategy for the direct, ultrasensitive, and specific luminescent turn-on sensing of perchlorate particulates is proposed by triggering supramolecular self-assembly of cationic platinum(II) complex in a hydrogel matrix, in which the self-assembly of platinum(II) complex endows the luminescence turn-on response and the hydrogel matrix creates excellent confinement effect for terminating the diffusion of generated luminescent 1D aggregates. The proposed hydrogelbased sensor is capable to detect the airborne perchlorate particulate of 1.12 ng by naked eye and 0.11 fg by common optical microscope. Further practical sensing performances for real firecracker and buried perchlorate in soil demonstrates the excellent environmental adaptability, and the latent fingerprint visualization shows great potential for clue tracking. This study provides an inspirable strategy for designing ultrasensitive luminescent sensor for trace solid sample.