The invention discloses an optimal coding method of general packet radio service (GPRS) based on networking monitoring. The method comprises the following steps: a transmitting terminal decides whether to perform the variable coding according to the response message from a receiving terminal by means of networking monitoring; a threshold of bit error rate is set; when the bit error rate of C2 coding is larger than the threshold, C1 coding is adopted; and when the bit error rate of C1 coding is less than the threshold, C2 coding is adopted. The implementation of adaptive coding enables the synchronization of both sides of communication based on the handshake mechanism. In the design, the optimal coding method further ensures and controls the reliability of frame reception by use of the following two measures: in one measure, setting a timer, if not receiving the feedback of the opposing side within the specified feedback period, determining that the rate change is in failure and re-transmitting at the original rate; in the other measure, transmitting the acknowledgement signal repeatedly for three times during the handshake process, and completing the coding although the transmitting side receives the signal only once, thereby improving the reliability of variable coding. The coding method is easy to implement and has high feasibility.