The invention discloses a sectional modifying completion method. The method includes the steps that a sectional modifying completion tube column is placed into a well shaft from the well mouth througha feeding tube column, and a suspension packer and a casing are sealed; setting and sealing checking are carried out on the suspension packer, the feeding tube column is separated from the sectionalmodifying completion tube column, and the feeding tube column is lifted; the feeding tube column is inserted into the sectional modifying completion tube column again, and packer particles are pressedinto the annulus between the sectional modifying completion tube column and the ground layer; the feeding tube column and the sectional modifying completion tube column are separated, surplus packerparticles in the feeding tube column are washed out and then lifted out of the feeding tube column from the well mouth; an acid fracturing tube column and a casing packer are placed into the well shaft; a differential pressure sliding sleeve on the sectional modifying completion tube column is subjected to pressing and acid fracturing; a plurality of ball-dropping sliding sleeves gradually close to the top end of the sectional modifying completion tube column are subjected to multiple times of ball-dropping pressing and acid fracturing; a well is opened; the acid fracturing tube column and thecasing packer are lifted out, a fishing tube column is placed in, and the packer particles are discharged out of the annulus through well washing.