Objective：Aims at the brittleness regulation of fruitand vegetable slices during hotair drying process.Methods：Thisarticle takes fresh potatoes and bananas as the researchmaterials， adopts mechanical and acoustic measuring devices tocollect mechanical and acoustic signals generated by the fruit andvegetable slice samples at the mechanical compression mode，which were collected at different drying times during the hotairdrying process of 80℃， to comprehensively evaluate the fragility of the fruit and vegetable slices.Results：The acoustic emission(AE) signal of the potato slice appeared the drying time of45min， and its AE energy increased gradually with the increaseof drying time.The stress increased rapidly and then remainedstable； The best drying endtime of potato was 180min.At thistime， the AE energy and force were 255.38mV·ms and 20.25Nrespectively.The A Esignal of the banana slices appeared fromthe early stage of drying， and its energy increased rapidly withthe progress of drying， decreased after 150min of drying， and re-mained stable after 200min， The stress appeared after drying for60min， increased rapidly until the peakat240min， andremained stable.The optimum drying endtime of banana sliceswas 240min， and the energy and force were 122.58mV·ms and18.01N， respectively.Conclusion：Themechanical-acousticde-tecting method can be used to monitor the crispness variation ofthe fruit and vegetable slices being dried and to optimize the hotair drying process.