We synthesize a series of pyridinyl salicylaldehyde based fluorescence sensor, which can selectively respond to Zn2+, besides, the detection of limit is 10-7M, and we utilize PL to identify the fluorescence mechanism. These derivatives subsequently dope to cholesteric liquid crystal as a chemosensor, which can detect metal ions by changing the pitch of cholesteric liquid crystal phase, then we can see the change of color by eyes. We compare different probe to detect different metals in liquid crystal sensor. At first, the color of liquid crystal mixtures CNNP and CNP is orange. after CNNP complex zinic ion (Zn2+) and CNP complex iron(III) ion (Fe3+), both of them change to green. Here we use UV-Vis to identify the reflected band of color and use CD to measure whether adding metal ions will change molecule chirality or not.