To address the global climate change issues, polymer electrolyte fuel cells (PEFCs) are receiving attention as electrochemical energy conversion devices employing green hydrogen. Notably, the PEFC fuel cell is because the electrochemical reaction occurs on the Catalyst Layer (CL), the CL is the core of the Membrane Electrode Assembly (MEA). The conventional CL is usually prepared from catalyst ink comprising the various catalyst, ionomer, and solvents and deposited via blade coating to the decal substrate. Therefore, it is necessary to confirm the optimal decal transfer conditions based on analyzing the characteristics of the catalyst ink and the decal substrate. In the study, the characterize the internal microstructure of the catalyst ink was confirmed through rheology, and the coating velocity was tunable based on catalyst property. In addition, the characteristics of the various decal substrate were confirmed through Atomic Force Microscopy (AFM) and Contact Angle, and differences including variations in loading amount were confirmed despite the same slurry. The structure of CL on the decal sheet was confirmed through a scanning electron microscope (SEM) surface image and cross-section image, and the distribution of Pt and ionomer was confirmed through Energy Dispersive X-Ray Spectrometer (EDS) mapping. The definition of electrochemical performance between catalyst ink characterizes and decal substrates property was investigated through polarization curves and electrochemical impedance spectroscopy (EIS). Also, cyclic voltammetry (CV) techniques are used to characterize electrochemical surface areas (ECSA) areas of the CL. As a result, the property between the catalyst ink and the decal substrate, based on the difference that occurs in the rheology characterized in the catalyst ink, leads to a variation in the CL structure. Therefore, it is very important to determine the decal process conditions by understanding the characteristics of various catalyst ink on rheology and decal sheet.