Recently,along with the environmental problems getting more and more serious,simultaneous monitoring temperature,pH and dissolved oxygen is an urgent task to understanding the dynamics and distribution between marine sediment and seawater[1,2].Due to its high sensitivity,low cost,rapid detection characteristics,fluorescence sensors have caught a lot attention in recent studies[3].Herein,we present a novel,inexpensive,fast fluorescence sensitive coating sensor that can be simultaneous sensing and imaging temperature,pH and dissolved oxygen with a single excitation.The triple sensor was based on chitosan as sensor matrix which is highly biocompatible and stable in ocean environments [4].Chitosan emitted fluorescence in 450 nm after adding cross linking agentglutaraldehyde,which intensity decreased with temperature raising.So the chitosan matrix served as a temperature indicator as well.Poly(styreneacrylonitrile)particles dopped with a luminescent meso-tetrakis(pentafluorophenyl)porphyrinato] platinum(Ⅱ)(PtTFPP)(emitting in 645 nm)probe were used for oxygen.And the pH probe Fluorescein isothiocyanate(FITC)emitting in 520 nm was covalently attached on the chitosan surface to achieve fast,high resolution response towards pH.A 385 nm ultraviolet lamp was used to excite the fluorescence sensor.The pH sensing and oxygen sensing showed no spectrum cross-sensitivity to each other.Both pH and oxygen signal should be rectified according to temperature.Moreover,the presented sensor demonstrated good photostability in seawater for months without obvious fluorescence attenuation.The most attractive feature of the presented triple sensor was making use of the blue,green,red emission,which enabled sensing and imaging via a RGB camera.The resolution of temperature,pH and dissolved oxygen was 1℃,0.5 and 2 mg/L respectively.