The accurate, ultrasensitive and rapid onsite analysis of perchlorate either in water, soil or air is urgently needed for public security checking, explosive ordnance disposal, environment monitoring and forensic analysis. To achieve it, a Pt(ii) terpyridyl complex-based sensing platform that can realize the onsite ultrasensitive, colorimetric and luminescent dual-mode, rapid and direct detection of perchlorate in water, soil and air was successfully developed by systematic molecular design. The high-contrast color change from pale-yellow to purple-red and turn-on mode red luminescent emission can greatly eliminate environmental fluctuations and background autofluorescence, thus enabling the detection of perchlorate more accurately, discriminatively and efficiently even in a complex environment. The excellent water-solubility of the Pt(ii) terpyridyl complex and the introduction of the hydrogel matrix largely enhance the sensing capacity and achieve the direct ultrasensitive detection of perchlorate microparticulates in soil or air, with a limit of detection of 0.45 ng by naked eye and 0.02 fg by common optical microscope. The present study provides a valuable strategy for designing a Pt(ii) complex-based sensor with high-contrast color change, high signal-to-noise ratio luminescence, and ultrasensitive detection ability for particulate analytes, which would shine light on the design of high-performance sensing platforms for various analytes.