Abstract: Abstract: Diesel engines are widely applied in the field of transportation and manufacturing because of its better power and fuel economic performances. However, diesel engine emits huge quantities of particulate matter (PM) which pose a great threat to the human health and environment. As emission regulations are becoming gradually stricter, it is imperative to stringently control diesel PM emission with a feasible after-treatment technic. Diesel particulate filter (DPF) is considered as the most effective mean to reduce diesel PM emission. The core of DPF regeneration is the control of upstream temperature of DPF. DPF regeneration is mainly divided into active and passive regeneration, the regeneration temperature is mainly controlled by the air management and injection strategy for the active regeneration. Air management is mainly by changing the intake throttle valve to control the intake air flow, and then controlling the exhaust temperature, which is important to match and improve the low temperature performance of the after treatment system, but the change of intake air flow will inevitably affect performances of the engine. So the control strategy of air management needs to be studied in depth. In order to obtain the intake throttling control strategy based on DPF active regeneration temperature under the whole working area of diesel engine, three typical working conditions were designed, including low-speed light load (working condition A:1 250 r/min 25% load), middle-speed medium load (working condition B: 2 000 r/min 40% load) and high-speed heavy load (working condition C: 3 000 r/min 70% load), and the effects of intake throttle opening on pumping loss, exhaust thermal condition, in-cylinder combustion and emission characteristics of diesel engine were studied. The experimental results showed that the throttle effect was enhanced, the air intake flow gradually reduced under the different working conditions with the increasing of the throttle valve opening, which lead to the deterioration of combustion in cylinder, the decrease of the maximum combustion pressure, the increase of the BSFC, CO, NOX and smoke emissions. However, the decrease of the intake air flow delayed the start timing of combustion, prolonged the ignition delay period and increased the combustion temperature as well as the exhaust temperature, which inhibited the generation of HC effectively. When the intake throttle valve opening was reduced to 20%, the reduction rate of air intake flow was greater under the low-speed light load condition, the increase rate of exhaust temperature was more significant as much as 63%, while under the heavy load conditions, the exhaust temperature was slightly increased, but the pumping loss was increased by up to 19.2%, which seriously deteriorate the fuel economic performance. Based on the experimental results, the intake throttle valve opening was set respectively 35%-45%, 50%-60% and 70%-80% range according to the increasing potential for the exhaust temperature and performance deterioration under working conditions A, B, C in this paper. Moreover, the intake throttling strategy was given within the scope of all working conditions based on exhaust temperature distribution of the engine that light loads adopted the larger intake throttle valve opening, with the increasing of load, the throttle valve opening was gradually increased to the full open state.