Phosphorus doped diamond-like carbon (DLC) films were firstly synthesized by the electrolysis of methanol-Triphenylphosphorus (PPh3) solution under high voltage, atmospheric pressure and low temperature. The microstructure and morphology of the as-deposited films were analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. The measurements results suggested that phosphorus doping enhanced the carbon films graphitization and the doped phosphorus existed mainly in CP bonds with the P/C ratio of 0.034. The P-DLC films have larger surface roughness compared to the DLC film. Moreover, the formation of P-DLC films in liquid-phase electrodeposition was via the reactions of the –CH3 and –P groups to form CPx network.