A certain plant located at an altitude of more than 2 200m had been put into operation for many years, the energy consumption and emissions could not meet the increasingly stringent national standard. After diagnosis on site, the energy-saving transformations were implemented including the preheater, calciner, exhaust gas treating system, kiln and tertiary air duct, cooler, etc. The upgrade project was completed and accepted in July, 2018. After the transformation, the clinker heat consumption was reduced by 438.9kJ/kg.cl, and the power consumption of the clinker was reduced by 6.1kW·h/t.cl. Since it was put into production for more than one year, the system has been operating stably and has reached the expected technical transformation target.