A sensing system on chip (SoC) is disclosed. The sensing SoC includes a substrate constructed on a CMOS platform; a thermometer formed on the substrate; a humidity sensing unit formed on the substrate and having a first heating unit; an air pressure sensing unit formed on the substrate; and a gas sensing unit formed on the substrate and having a second heating unit, wherein the humidity sensing unit, the air pressure sensing unit, and the gas sensing unit are laterally distributed on the substrate. |