The invention relates to a mobile phone code-scanning system based on image processing. The system comprises light quantity detection equipment arranged on a mobile phone, and used for detecting the surrounding light quantity of position located by the mobile phone, and outputting the surrounding light quantity; light quantity compensation equipment connected with the light quantity detection equipment and used for receiving the surrounding light quantity, and performing light quantity compensation on the position located by the mobile phone when the surrounding light quantity is less than andequal to a preset light quantity threshold, wherein the sum of the light quantity compensation strength and the surrounding light quantity strength is the preset light quantity strength value; pattern scanning equipment for scanning an identification code pattern in front of the mobile phone so as to acquire and output the identification code pattern; rotary processing equipment used for receiving the identification code pattern, acquiring the placing angle of each object in the identification code pattern, and correcting the placing angle of each object in the identification code pattern based on the preset angle threshold. Through the mobile phone code-scanning system disclosed by the invention, the precision of the mobile phone payment is further improved.