Disclosed are a method and device for data compression, transmission, and decompression. In the present method, data-to-be-transmitted is grouped by a transmitting terminal, and for each group: a shift factor is determined based on the most significant bit of sample data of the greatest value in the group when a sign bit is removed, data bits of the sample data in the group are left shifted by the shift factor; the left shifted sample data respectively are quantified, thus making the bit number of the quantified sample data to be equal to a predefined bit number; the shift factor and the quantified sample data are transmitted to a receiving terminal. Employment of the present application optimizes data compression performance.