Image　histogram　is　a　simple　but　important　concept　in　digital　image　processing.　It　is　not　changed　with　image　translation,　rotation,　scale,　andetc.,　which　makes　it　be　widely　used　in　image　feature　extraction,　image　segmentation,　image　matching,　image　classification,　contrast　enhancement　and　so　on.　With　the　development　of　quantum　image　processing,　it　is　also　necessary　to　perform　the　histogram　statistics　of　images　on　quantum　computers.　However,　since　all　pixels　in　a　quantum　image　are　stored　superposedly,　it　is　difficult　to　solve　the　problem　of　counting　the　number　of　pixels　with　a　certain　color.　This　paper　proposes　a　method　for　calculating　the　quantum　image　histogram,　based　on　the　quantum　adder　for　superposition　states.　It　uses　control　qubits　to　determine　whether　the　color　information　of　a　quantum　image　and　the　index　information　of　the　quantum　histogram　are　equal　to　a　particular　value.　If　this　is　the　case,　the　quantum　adder　for　superposition　states　counts　the　number　of　pixels　with　that　color.　This　scheme　not　only　solves　the　problem　of　histogram　statistics　in　quantum　image　processing,　but　also　reduces　the　complexity　of　classical　histogram　statistics　fromO(2(2n))　toO(2(q)),　wherenis　related　to　the　image　size　andqis　related　to　color　numbers.