An AA novel ratiometric biosensor based on PCN-333 (Al) MOFs-KB-Thi was prepared. PCN-333 (Al) MOFs could effectively avoid the cohesion or aggregation of KB and Thi on electrode surface. PCN-333 (Al) MOFs could selectively accumulate target analytes into their pores to enhance the selectivity. The ratometric biosensor could improve the accuracy and reproducibility. The AA ratiometric biosensor showed good performance toward AA detection.