Due to their industrial interest and significance, developing a rapid method for screening β-xylosidase activities would certainly facilitate the research and improve production in xylan-related industries especially in the pulp and paper industries. Here we report the synthesis of two activity probes, LCL-6X and -12X, for β-xylosidase. They both carry a β-xylopyranosyl recognition head, which is linked to a latent trapping device consisting of a 2-fluoromethylphenoxyl group and a biotin reporter group. They differ only in the length of their hydrophobic linker. A model study using a β-xylosidase from T. koningii demonstrates that both probes could successfully label the target hydrolase and give rise to biotinylated proteins. They could thus potentially become a powerful tool in screening β-xylosidase from microbial sources.