A physicochemical water treatment process using a microfiber filter coated with a coagulant, the process comprising: a) performing a pressurized filtration by supplying raw water to an upper portion of a pressurized microfiber filtering device including a microfiber filter coated with a coagulant; b) backwashing the microfiber filter by supplying backwashing water and air from a lower portion of the microfiber filtering device; and c) after the backwashing of the microfiber filter is completed, coating the microfiber filter with the coagulant by supplying the coagulant together with the backwashing water, wherein the pressurized microfiber filtering device includes: a pressurized housing having an upper portion connected to a raw water supply port; the microfiber filter provided inside the pressurized housing to filter the raw water and having an upper end portion fixed to a flow holder; a porous permeable pipe disposed in a lower portion of an inside of the microfiber filter to pass filtered treatment water, backwashing water, and air; a filtered water and backwashing water distribution port connected to a lower portion of the porous permeable pipe to discharge filtered water and supplying the backwashing water; and an air supply pipe connected to the lower portion of the porous permeable pipe to supply air, treatment water that has been subjected to a pressurized filtration processing is transferred to a treatment water storage tank, and some of the treatment water is transferred to a backwashing water storing bath to be used as backwashing water, backwashing wastewater resulted from the backwashing of the microfiber filter is transferred to a suction type filtration tank, and the backwashing wastewater stored in the suction type filtration tank is supplied to a suction type micro fiber filtering device to be filtered, and the suction-filtered treatment water is returned to a raw water storing bath, and some of the suction-filtered treatment water is transferred to a suction type microfiber filtering device backwashing water storing bath. a) performing a pressurized filtration by supplying raw water to an upper portion of a pressurized microfiber filtering device including a microfiber filter coated with a coagulant; b) backwashing the microfiber filter by supplying backwashing water and air from a lower portion of the microfiber filtering device; and c) after the backwashing of the microfiber filter is completed, coating the microfiber filter with the coagulant by supplying the coagulant together with the backwashing water, wherein the pressurized microfiber filtering device includes: a pressurized housing having an upper portion connected to a raw water supply port; the microfiber filter provided inside the pressurized housing to filter the raw water and having an upper end portion fixed to a flow holder; a porous permeable pipe disposed in a lower portion of an inside of the microfiber filter to pass filtered treatment water, backwashing water, and air; a filtered water and backwashing water distribution port connected to a lower portion of the porous permeable pipe to discharge filtered water and supplying the backwashing water; and an air supply pipe connected to the lower portion of the porous permeable pipe to supply air, a pressurized housing having an upper portion connected to a raw water supply port; the microfiber filter provided inside the pressurized housing to filter the raw water and having an upper end portion fixed to a flow holder; a porous permeable pipe disposed in a lower portion of an inside of the microfiber filter to pass filtered treatment water, backwashing water, and air; a filtered water and backwashing water distribution port connected to a lower portion of the porous permeable pipe to discharge filtered water and supplying the backwashing water; and an air supply pipe connected to the lower portion of the porous permeable pipe to supply air, treatment water that has been subjected to a pressurized filtration processing is transferred to a treatment water storage tank, and some of the treatment water is transferred to a backwashing water storing bath to be used as backwashing water, backwashing wastewater resulted from the backwashing of the microfiber filter is transferred to a suction type filtration tank, and the backwashing wastewater stored in the suction type filtration tank is supplied to a suction type micro fiber filtering device to be filtered, and the suction-filtered treatment water is returned to a raw water storing bath, and some of the suction-filtered treatment water is transferred to a suction type microfiber filtering device backwashing water storing bath.