Abstract: On account of the malodor complaints in a residential area in Shanghai, a research on the sources, characteristics and risk assessment of malodorous substances was conducted. The positive matrix factorization (PMF) model was used to conduct the source analysis of the continuous monitoring data of the residential area's malodor point, and three emission sources were identified, which were kitchen waste source (41.24%), agricultural source (32.85%), and mixed source of secondary generation and exhaust emission (25.91%), and the kitchen waste source was the main source of the residential area's malodor. By analyzing the correlation of the odor active values (OAV)of the main odor-causing substances among the monitoring points, it showed that the residential area was mainly affected by the odor pollution of the pretreatment and biochemical workshops, and the degree of influence throughout the day had the characteristics of intermittent change. By calculating the ozone formation potential (OFP) of the malodorous substances in the exhausts of the pretreatment, biochemical treatment and further processing workshops, it was found that the OFP contributions of each species were carbonyls (37.46%), alcohols (21.38%), olefins (15.52%), volatile fatty acids (13.7%), aromatic hydrocarbons (4.02%), nitrogenous compounds (3.90%), alkanes (1.77%), esters (1.29%), sulfide (0.95%) and chlorinated organic substances (0.01%), so carbonyl group, alcohols, olefins, volatile fatty acid substances were representative species of OFP contribution in the plant. OFP of each workshop in descending order was pretreatment workshop (27 051.82 μg/m³), biochemical workshop (7 547.51 μg/m³), deep processing workshop (1 647.14 μg/m³), in which acetaldehyde, acrylic acid, 1-butene, formaldehyde, ethanol, propylene, and phenol were the main ozone-generating pollutants in the kitchen waste treatment plant, and acetaldehyde had the highest OFP contribution radio in the three exhausts. Results of the health risk evaluation of the odorous substances at the sensitive point showed that the non-carcinogenic risks and cumulative carcinogenic during the monitoring period exceeded the safety threshold recommended by U.S. EPA, and the main contributing species were acrolein and formaldehyde, respectively. Therefore, acetaldehyde, acrolein, and formaldehyde should be prioritized as indicators of malodorous substances in food waste treatment plants.