New electrochemical mechanisms of chlorpromazine (CPZ) as one of the derivatives of phenothiazine and chlorpromazine in the presence of l-cysteine as an amino acid at 0.3 - 1.3 V on boron-doped diamond (BDD) electrode surface were studied using cyclic voltammetry (CV) technique for the frst time. The results indicated that the electrochemical oxidation mechanism of chlorpromazine is EEC. Furthermore, the results of studying the electrochemical behavior of chlorpromazine in the presence of l-cysteine shows an electrocatalytic mechanism. According to these results, this system is implicated in the EC’EC mechanism. For both mechanisms, we studied the impact of increasing the concentration and rate of potential scanning. Digital simulation (Digital Simulation3 program) analyses were conducted using these mechanisms for cyclic voltammograms obtained on the borondoped diamond electrode surface. Kinetic data were extracted from these voltammograms through digital simulations to estimate the heterogeneous rate constant (ks), equilibrium constant (Keq), charge-transfer coeffcient (α), chemical rate constant (kc) and diffusion coeffcient (D) by comparing the experimental responses with the simulated results.