A series of surfactant-modified zeolites (SMZs) were prepared by loading various amounts of cetylpyridinium bromide (CPB) onto the external surface of natural zeolites, and their CPB coverage types were determined by comparing the loading amounts of cetylpyridinium (CP+) and bromide (Br-). The behavior and mechanism of Congo red (CR) adsorption onto SMZs with different coverage types were investigated. The SMZ was effective for the removal of CR from aqueous solution. The SMZ with higher CP+ loading amount exhibited higher CR adsorption capacity. The amount of CR adsorbed on SMZ was found to increase with an increase in contact time and initial dye concentration but was found to decrease with increasing adsorbent dosage. Coexisting Cu(II) in solution favored CR adsorption onto SMZs. The kinetic data of CR on SMZs followed a pseudo-second-order model. The equilibrium adsorption data of CR on SMZs were well described by the Langmuir isotherm model. For SMZ with monolayer coverage, hydrophobic interaction was the main mechanism for CR adsorption. For SMZ with bilayer coverage, anion exchange, and organic partitioning were the main mechanisms for CR adsorption. For SMZ with patchy bilayer coverage, anion exchange, organic partitioning and hydrophobic interaction were the main mechanisms for CR adsorption.