Protein Tyrosine Phosphatases (PTPs) and Protein Tyrosine Kinases (PTKs) are two enzyme families which control protein tyrosine dephosphorylation and phosphorylation reactions. Reversible tyrosine phosphorylation plays critical roles in regulating cellular activities such as growth, differentiation, metabolism and signal transduction. Thus, aberrant activities of these enzymes have been implicated in many human diseases including tumors and cancer. Among the PTP superfamily, they share a conserved signature motif, HC(X)5R(S/T), in their active site. The nucleophilic cysteine dominates the catalytic mechanism of dephosphorylation process. In this work, we focused on this structural feature and developed specific active site probes for PTPs in the hope that they could be used to profile intracellular PTP activities. We have designed and synthesized four chemical probes for PTP enzyme family. Those probes carry the same tetraethylene glycol linker and biotin reporter but differ in their reactive groups which consist of ,-unsaturated structure as phosphotyrosine mimetics. Later we investigated the reactivity between our probes and PTPs to see if they can covalently modify of active site cysteine through Michael addition. Labeling results showed that two of our chemical probes form covalent adducts with the PTPs tested (SHP2, TCPTP and VHR) and the probes are specific toward PTPs. 　　In second part we synthesized two fluorescent probes based on the previous PTPs reactive structure but used FQCA fluorophore as reporter. The fluorescent probes provided higher detection sensitivity and they could further be used to examine the labeling site of our probes on PTPs by processes of protein labeling→ digested by trypsin→ HPLC separation and fluorescence detection→ Mass analysis.