Abstract: SINOPEC Maoming Branch has made technical improvement to cracking heater of H110，H113，H114，H116，H117 and H120 in 1# pyrolysis cracking unit from 2009. This paper reports the comparison in running status of H116 and H117 before and after the technical improvement. Industrial running data showed that the radiant heat transfer efficiency has been improved greatly after improvement，the combustion consumption of the heater was lowered by 11% for the same procession amount，the emission of CO2 was largely reduced and the processing capacity of the heater was increased obviously，which made great improvement in both economical and environmental return of the unit.