Currently， microchannel reactors are extensively employed in the synthesis of energetic materials， significantly enhancing the safety of the synthesis process. However， it is still crucial to consider the thermal stability of these materials. Two important parameters that characterize the risk of thermal decomposition for hazardous chemicals and energetic materials are the time to maximum rate under adiabatic conditions（TMR_ad） and the initiation temperature（T_D24）， which corresponds to the time to maximum rate within 24 hours. The traditional calculation methods for these two parameters are the single-step N-order method and numerical calculations， which have drawbacks such as being time-consuming and labor-intensive during analysis. To address this issue， this study proposes a method for calculating characteristic parameters of thermal runaway decomposition based on the first peak observed after splitting a multi-peak curve in dynamic test curves obtained from Differential Scanning Calorimeter（DSC）. Furthermore， a comparison between this paper’s method and a modeling method using an exhaustive approach was conducted by evaluating T_D24 deviation. Numerical simulation was employed for verification purposes， enabling calculation of thermal runaway characteristic parameters of four substances， namely 1，8-dinitroanthraquinone， M-NQ， 1，5-dinitroanthraquinone， and DNTF based on literature experiments. The results indicate that numerical simulations demonstrate a maximum percentage T_D24 deviation of 2.88% and 6.9% for two-step and three-step consecutive reactions respectively. The maximum deviation observed was 6.41 ℃； for three-step continuous reactions， the T_D24 exhibited a maximum deviation of 5.39 ℃. Furthermore， experimental results employing the methodology proposed in this study demonstrated that the T_D24 values for four energetic materials were calculated with the deviations of -4.55 ℃， 0.71 ℃， 3.16 ℃， and -0.84 ℃ respectively； all absolute percentage deviations were less than 2% when compared to T_D24 obtained through model calculations. These findings validate the effectiveness of the proposed T_D24 calculation method presented in this paper as it exhibits minimal deviation during calculation while offering a straightforward computational process capable of accurately determining thermal decomposition runaway characteristic parameters.