The invention discloses a method and a device for determining a person number in a people stream of an area. The method comprises the steps of determining a core base station set and an associated base station set according to a position relationship between at least one area which is divided by each base station and a statistical area; determining a person number interval to which the person number that corresponds with the core base station set belongs from a plurality of preset person number intervals; according to the person number interval to which the person number that corresponds with the core base station belongs, after a fact that the person number of the statistics area needs adjustment is determined, determining the type of the statistical base stations in the associated base station set; determining a dynamic adjusting person number according to the person number of the base station which corresponds with the type of each statistical base station in the associated base station set; and using summation of the person number which corresponds with the core base station set and the dynamic adjusting person number as the person number of the statistical area. The method and the device for determining the person number in the people stream of the area can obtain a more accurate person number.