This paper is devoted to the practical fixed-time optimal consensus problem for disturbed multi-agent systems under dynamic event-triggered mechanism. In order to derive a more accurate upper bound of the settling time, a new practical fixed-time stability criterion is obtained. Then, a distributed optimization algorithm with hyperbolic tangent function is constructed, and the dynamic event-triggered mechanism is introduced and the corresponding consensus control protocol is designed. Moreover, by designing the parameters in the control protocol, the impact of disturbances on system stability can be effectively mitigated. Finally, a numerical example is included to demonstrated the effectiveness of the proposed results.