The present invention discloses a water purification filter easily replaced by a connector which can simplify a connection structure of a water purification system by forming paths of feed water, purified water and concentrated water as one port, and which can be easily replaced after disconnection of a filter cartridge from the water purification system, and a water purification system using the same. The water purification filter easily replaced by the connector includes a connector having an inflow hole through which feed water flows in, a check valve body in which a check valve for opening/closing a feed water flowing path for guiding feed water to a filter side and a concentrated water discharge path are formed, an outflow hole for externally discharging purified water, and a concentrated water control hole for externally discharging concentrated water, a filter housing for opening the feed water flowing path by opening the check valve in connection with the connector, a locking means for detachably fixing the filter housing to the connector, and a passage switching guide having a first path for supplying feed water to a reverse osmosis membrane filter when the filter housing is connected to the connector, a second path for supplying water purified by the reverse osmosis membrane filter to the outflow hole, and a third path for supplying concentrated water to the concentrated water discharge path.