A hydroxylated carbon nanotubes/platinum nanoparticles/rhodamine B nanocomposite modified glass carbon electrode (CNTs-OH/PtNPs/RhB/GCE) was developed by a simple and environment-friendly method to determine 2,4,6-trichlorophenol (2,4,6-TCP) and 4-chlorophenol (4-CP), which usually coexist and interfere with each other. Owing to the excellent electron transfer and catalytic property, the CNTs-OH/PtNPs/RhB/GCE significantly facilitated the electro-oxidation of 2,4,6-TCP and 4-CP. The enhanced oxidation peak currents of the two chlorophenols were simultaneously determined with relatively large separation of peak potential (91 mV). Under optimized conditions, the sensor showed a linear response toward 2,4,6-TCP in the range of 5.0-175.0 mu M with the detection limit of 1.55 mu M (S/N = 3). The linear concentration range for 4-CP was 10.0-300.0 mu M, and the detection limit was 3.69 mu M (S/N = 3). Furthermore, the proposed sensor was successfully used for the analysis of 2,4,6-TCP and 4-CP in water samples with the recoveries of 96.8-102.8% and 95.6-103.2%, indicating a promising potential in practical application.