A pet groomer for use in conjunction with a vacuum cleaner, comprising: a main body comprising a hollow front section, a handle for a user to hold when grooming a pet, a suction channel for connecting with said vacuum cleaner, a combing assembly comprising a rotating body which is rotatably installed in said hollow front section, wherein at least one comb teeth group is set on said rotating body, each of said comb teeth group comprising plurality of comb teeth distributed in an axial direction of said rotating body and extending outwardly from said rotating body, a driving assembly for driving said comb teeth to rotate between a first position and a second position, and a comb use opening, set on said hollow front section, from where said comb teeth can extend outwardly for grooming the pet, characterized in that: the pet groomer further comprises an air leakage opening, set on said main body for introducing air into said main body at the same time as said comb use opening, when said pet groomer is connected to a working vacuum cleaner and said at least one comb teeth group is in said first position, said comb teeth extend outwardly from said comb use opening for grooming, said air leakage opening introduces airflow into said main body to reduce a suction force at said comb use opening and prevent excessive suction on the pet's body when said comb use opening is blocked by the pet's body during grooming, and when said comb teeth group is in said second position, the teeth of said comb teeth group are rotated to point inside of said main body, and airflow from both said air leakage opening and said comb use opening go through said comb teeth in the same time. a main body comprising a hollow front section, a handle for a user to hold when grooming a pet, a suction channel for connecting with said vacuum cleaner, a combing assembly comprising a rotating body which is rotatably installed in said hollow front section, wherein at least one comb teeth group is set on said rotating body, each of said comb teeth group comprising plurality of comb teeth distributed in an axial direction of said rotating body and extending outwardly from said rotating body, a driving assembly for driving said comb teeth to rotate between a first position and a second position, and a comb use opening, set on said hollow front section, from where said comb teeth can extend outwardly for grooming the pet, characterized in that: the pet groomer further comprises an air leakage opening, set on said main body for introducing air into said main body at the same time as said comb use opening, when said pet groomer is connected to a working vacuum cleaner and said at least one comb teeth group is in said first position, said comb teeth extend outwardly from said comb use opening for grooming, said air leakage opening introduces airflow into said main body to reduce a suction force at said comb use opening and prevent excessive suction on the pet's body when said comb use opening is blocked by the pet's body during grooming, and when said comb teeth group is in said second position, the teeth of said comb teeth group are rotated to point inside of said main body, and airflow from both said air leakage opening and said comb use opening go through said comb teeth in the same time. the pet groomer further comprises an air leakage opening, set on said main body for introducing air into said main body at the same time as said comb use opening, when said pet groomer is connected to a working vacuum cleaner and said at least one comb teeth group is in said first position, said comb teeth extend outwardly from said comb use opening for grooming, said air leakage opening introduces airflow into said main body to reduce a suction force at said comb use opening and prevent excessive suction on the pet's body when said comb use opening is blocked by the pet's body during grooming, and when said comb teeth group is in said second position, the teeth of said comb teeth group are rotated to point inside of said main body, and airflow from both said air leakage opening and said comb use opening go through said comb teeth in the same time.