The utility model relates to a condensation hot water boiler with externally-arranged condensers, which comprises a boiler casing (4), a boiler furnace (3), a reversal chamber (6), a front smoke box (2), a convection tube bundle (7) and a burner (1). The boiler furnace (3), the reversal chamber (6) and the convection tube bundle (7) are all arranged in the boiler casing (4). The front smoke box (2) is arranged on the outside of the boiler casing (4). The tube pass of the convection tube bundle (7) is communicated with the front smoke box (2) and the reversal chamber (6). The condensation hot water boiler with the externally-arranged condensers is characterized in that a condenser I (8) and a condenser II (9) are independently arranged at the top or on the outside of the boiler casing (4) in parallel. Return water parallelly enters the condenser I (8) and the condenser II (9) through a condenser water inlet main pipe (10) in two ways. Outlet water from the condenser I (8) and the condenser II (9) is collected to a condenser water outlet main pipe (11) and flows to the boiler casing (4) of the hot water boiler. The condensation hot water boiler with the externally-arranged condensers can reduce the exhausted smoke temperature of the boiler to be low enough and enables water vapor in overheating state in the smoke to be condensed into liquid water and release latent heat of vaporization.