The filling, pretreatment of new catalyst of BASF 0466 and the changing of hot spot temperature when the material entered the reactor were investigated. It was found that the activity of catalyst can be optimized by adjusting the air flowed into the reactor and the reactor temperature in pretreatment of the catalyst|while the reaction has begun, the hot spot temperature mainly focused on the catalyst layer of CL4, as the reaction proceeded, the hot spot temperature is gradually transferred to the position of the catalyst layer of CL1. The hot spot temperature from 3 050 mm to move to the position of 650 nm and 550 mm. The hot spot temperature rises from 410.5 ℃ to 431.5 ℃, the hot spot temperature increase of 5.1%.