The hydraulic valve spool of hand-operated pump of truck cab has long cylindrical mating surface with its mating hole,the sealing structure of O-ring exists serious leakage problem,and the manufacture of the spool and its mating hole is difficult.The sealing method combined wear pad and O-ring was presented to apply for the seal of the oil hole of valve spool,the type of the wear pad and O-ring was selected and the structure was designed.The practical production and application prove that the leakage problem of handoperated pump is solved,and the difficulty of manufacturing of the spool and its mating hole is reduced greatly.