Catechins in tea, as promoters of human health, have attracted widespread attention. Herein, a dual-signal mode (colorimetric and fluorescence) sensor array for catechin species fingerprinting was built based on PtNi bunched nanoparticle (PtNi-BNP)-o-phenylenediamine (OPD)-H2O2 system. PtNi-BNPs catalyze the reaction between OPD and H2O2 to produce oxidized OPD (oxOPD) with both colorimetric (yellow) and fluorescent properties. As an antioxidant, catechins can inhibit the above reaction, resulting in a lighter color and reduced fluorescence intensity in the reaction solution. Owing to the varying inhibitory effects of different catechins on the reaction, they produce unique colorimetric-fluorescence response patterns. These diverse responses were recorded and processed using linear discriminant analysis (LDA), and six catechin species were identified using the sensor array. Furthermore, our work provides a convenient method for simultaneous differentiation of catechins in mixtures and real samples. Such a sensor array with minimal sensor element and abundant signal outputs considerably saves cost and time, thus providing a powerful tool for the discrimination and assessment of catechins.