Abstract: Abstract: Sweet cherry (Prunus avium L.), an economically important temperate fruit, is popular for its attractive red colour and high value of nutrients. However, sweet cherry is highly perishable and susceptible to mechanical injury and fungal decay. Penicillium expansum, the causal agent of blue mould, is a widespread fungal pathogen and causes considerable losses in sweet cherry fruit. Traditionally, the control of postharvest mould decay is mainly dependent on synthetic fungicides. However, the increasing resistance of fungal pathogens and growing concern of the public over chemical residues make it crucial to research alternative approaches to inhibit mould decay. Heat treatment, as a physical method, has acquired increasing attention and has been widely used to control fruit decay and maintain quality. There are 3 methods in use to heat fruit and vegetable: Hot air, hot water and hot water vapor. However, there is no information concerning the condition of hot air on inhibiting blue mold decay in sweet cherry fruit using the response surface methodology (RSM). RSM is a collection of mathematical and multivariate statistical techniques that are useful for the modeling and analysis of problems, in which a response of interest is influenced by several variables and the objective is to optimize the response. In order to determine the optimum condition of hot-air treatment on the inhibition of blue mould decay in postharvest sweet cherry fruit, the effects of different temperature-time combinations on inhibition efficiency of blue mould decay and fruit quality were investigated using the RSM. The fresh harvested sweet cherry fruits were treated in hot air at different temperatures (40-48 ℃) for different treatment time (60-180 min), then the fruits were inoculated with the spores of Penicillium expansum (5×104 CFU/mL) and stored under the condition of approximately 90%-95% relative humidity at 20 ℃ for 5 d. At the end of storage, lesion diameter of blue mould decay, fruit firmness, content of ascorbic acid and ratio of TSS (total soluble solids) to TA (titratable acidity) were measured. Four second-order quadratic equations of lesion diameter of blue mould decay, fruit firmness, content of ascorbic acid and ratio of TSS to TA were established, and the fitting degrees were also analyzed through the RSM. The key factors and their interactions affecting the inhibition efficiency of blue mould decay and fruit quality were also discussed through the RSM. By analyzing the response surface graphs and corresponding contour graphs as well as solving the quadratic equations, the results suggested that the optimum condition for combined treatment of hot air in sweet cherry fruit was that the temperature was 44 ℃, and the treatment duration was 114 min. Results of demonstration and comparison tests showed that the optimum condition (44 ℃, 114 min) obtained via the RSM effectively inhibited the blue mould decay in sweet cherry fruit and maintained the fruit quality. In comparison with the control fruit, hot-air treatment delayed the decline of firmness and ascorbic acid content and maintained a higher level of TSS/TA. The present study showed that the optimum parameters of hot-air treatment obtained by the RSM are feasible, which can provide a theoretical foundation for further research of the application of hot-air treatment in sweet cherry fruit preservation.