The invention relates to a magnetosonic imaging signal processing device and a processing method based on pulse code. A code stimulating sequence is generated by A code generator to be sent to a power amplifier, meanwhile, the code generator gives a rising edge signal to a pulse compressor used for carrying out pulse compression on a signal, the power of the code stimulating sequence is enhanced through the power amplifier to be loaded on a sample arranged in an acoustic couplant with a magnetic field to generate a magnetosonic response signal, the generated magnetosonic response signal is received by a transducer by virtue of spreading of the acoustic couplant, a signal output by the transducer is amplified by a preamplifier, the amplified signal is subjected to pulse compression by a the pulse compressor, and then the sound source distribution of the sample is obtained and output. According to the invention, by utilizing the stimulating method of pulse code and the detection method of pulse compression, magnetosonic coupling imaging lays foundation for the accurate imaging of lesion tissues of tumor and the like, and important diagnostic basis is laid for early diagnosis and accurate staging of medical clinical relevant diseases, especially tumor and other malignant diseases.