A simple procedure was developed to prepare a glassy carbon (GC) electrode modified with single wall carbon nanotubes (SWCNTs) and phenazine derivative of Mn-complex. With immersing the GC/CNTs modified electrode into Mn-complex solution for a short period of time 20–100 s, a stable thin layer of the complex was immobilized onto electrode surface. Modified electrode showed a well defined redox couples at wide pH range (1–12). The surface coverages and heterogeneous electron transfer rate constants (ks) of immobilized Mn-complex were approximately 1.58×10−10 molecm−2 and 48.84 s−1. The modified electrode showed excellent electrocatalytic activity toward H2O2 reduction. Detection limit, sensitivity, linear concentration range and kcat for H2O2 were, 0.2_M and 692 nA_M−1 cm−2, 1_M to 1.5mMand 7.96(±0.2)×103M−1 s−1, respectively. Compared to other modified electrodes, this electrode has many advantageous such as remarkable catalytic activity, good reproducibility, simple preparation procedure and long term stability.