A method and system of multimedia service performance monitoring is provided. The method comprises the following steps: (a) a reference point acquires and stores the association relationship between multimedia packet identification number and the corresponding multimedia information; (b) a sample point orders the received packets according to the multimedia packet identification numbers, detects the integrality of the packets, and feeds the identification numbers of the lost multimedia packets back to the reference point if there are lost packets; (c) the reference point obtains the corresponding multimedia information according to the identification numbers of the lost multimedia packets returned by the sample point and the stored association relationship between the multimedia packet identification number and the corresponding multimedia information, and then evaluates the multimedia service quality of the sample point.