2-Butyltetrahydrofuran is being investigated as a potential alternative fuel for diesel engines due to its self-ignition properties. This paper presents a reduced 2-butyltetrahydrofuran chemical kinetic mechanism for the first time, accompanied by an in-depth study of its combustion characteristics. N-heptane/toluene is a recognized surrogate mixture that effectively represents complex diesel for analyzing combustion behaviors. To achieve optimal combustion and application of 2-BTHF in diesel blends, this paper introduces a reliable mechanism for the 2-BTHF/n-heptane/toluene mixture for the first time. Firstly, directed relation graphs with error propagation, combined with isomer lumping and sensitivity analysis, are proposed to efficiently reduce detailed mechanisms, enhancing the approximation process in mechanism establishment. Results from the reduced 2-BTHF mechanism show that the cooperative methodology effectively diminishes the complexity of the detailed mechanism while improving its predictive capabilities. Secondly, the reduced 2-BTHF mechanism is combined and refined with those of n-heptane and toluene. Its accuracy is verified using diverse experimental data, including ignition delay times from shock tubes/rapid compressors and laminar flame speeds measured in combustion vessels. The final reduced chemical kinetic mechanism for the mixture comprises 78 species and 300 reactions, demonstrating significant potential for simulating the combustion behavior of 2-BTHF/n-heptane/toluene blends. Additionally, the study explores the impact of adding 2-BTHF to diesel fuel. Results reveal that increasing the proportion of blended 2-BTHF gradually raises the laminar flame speeds of diesel, while having minimal influence on ignition delay times.