Doosan DX300LC-9 has inspected and maintained the excavator, replaced the three filters, engine oil and excavator lubricant. All aspects of performance data meet the use requirements. Especially in the working test, it has a very perfect working performance. The engine power and speed test are normal, and the hydraulic flow of the excavator hydraulic pump is normal. Doosan DX300LC-9 can basically meet the use of various projects in various environments. The big guy with a deadweight of more than 30 tons is not very suitable for working in the city. The fuel consumption performance is average, and the working speed is still very satisfactory.