At about 12:00 on August 18, a crane in operation near Dajiaoting bridge in Chaoyang District overturned, and the 30 meter long jib hit the roof of the communication machine of China Mobile Corporation in front of it, bending. The head of the crane touched the ground, the body was vertical, and the oil tank under the crane was leaking oil. The smell of diesel oil was once diffused at the scene.

"The load is too heavy." Master Li, the driver, told the Beijing Youth Daily that a small bucket had been hung on the crane for operation. At noon, he replaced it with a large bucket. "The car was originally loaded with 2 tons, but it was increased to more than 3 tons in the afternoon, which was too much." After the car reversed, Master Li quickly opened the door and jumped out of the car and left the scene.

At about 2 p.m., the firefighters who received the alarm rushed to the scene and set up a warning line around the crane. The firefighters at the scene told the reporter of the Beijing Youth Daily that foam had been sprayed on the vehicle body and the ground twice. Since the oil tank of the crane is constantly leaking oil and the outdoor temperature is too high, in order to avoid fire and other accidents caused by open fire, three fire engines are parked at the accident site for standby.