This paper introduces the problems in the use of the original sealing scheme of pyrolysis fuel oil product pump in the 200 kt/a ethylene plant in Tianjin. The rationality of applying several sealing schemes stipulated in API682-2004 in the pyrolysis fuel oil product pump in the 200 kt/a ethylene plant in Tianjin is analyzed through the comparison of the advantages and disadvantages of the sealing schemes. The actual transformation scheme and application effect of the sealing scheme of pyrolysis fuel oil product pump are introduced.