Abstract: Authors made a great quantity of sampling analysis for regular cracks of steel light-hydrocarbon spherical tanks in service in Daqing and Jilin zone.It was proved that above cracks frequently-occurring in recent years are hydrogen sulfide stress corrosion cracks in the main,and it is difficult to control and repair for their.By means of the character and mechanism analysis of the regular cracks for spherical tanks and a serial of tests or research including the theoretical foundation of repairing technique,repairing technique approach,repairing material and condition test,heat treatment role and condition test,surface composite coatings role and coatings material and condition test,dipping test and simulate htdrogen sulfide stress corrosion crack test,engineering test et al,we developed a whole and comprehensive repairing technique:releasing hydrogen treatment,softening structure repair welding,local or whole heat treatment,spraying specific composite coatings.The technique has been put into engineering application,and dozens of damaging tanks whose volume are 120-1 000 cubic metres had been repaired successfully,and the coatings technique effectively restrained the cracking tendency of in-service tanks.