Cooking volatile organic compounds (VOCs) is an important source of indoor VOCs, which has attracted more attention in recent years with increasing concerns about indoor health. Having a better understanding on the emission and evolution of cooking VOCs will greatly benefit the understanding on the relevant indoor chemical processes and resulted health effects. In this study, a novel ambient MS-based method, namely secondary electrospray ionization high resolution mass spectrometry (SESI-HRMS), was used to monitor cooking VOCs in real time under simulated cooking conditions; the possible products from chemical reactions were tentatively identified. Significant difference has been observed between the VOCs before, during and after peanut oil cooking, demonstrating the fast evolution of primary cooking VOCs. The VOCs observed during cooking are consistent with that reported previously. Hundreds of features occurred when the cooking was stopped and this phenomenon has been attributed to the secondary VOCs produced during indoor chemical processes. The time-intensity signal curves indicate that nitrogen-containing heterocyclic compounds (e.g., pyrazine, pyridine), aldehydes (e.g., decadienal), fatty acids (e.g., palmitic acid, oleic acid) reach their peak levels, in turn. According to the chemical process of oleic acid (C18H34O2) in previous studies, the peaks at m/z 187.0966 and m/z 313.2380 are assigned to C9H16O4 and C18H34O4, which are supposed to be the oxidation products of oleic acid.