Dynamic Economic emission dispatch (DEED) considering transmission loss and valve-point effect is a non-linear constrained multi-objective optimization problem in thermal power system. The objective function of this problem is non-smooth and non-convex. To tackle this problem, a Pareto-based multi-objective marginal differential evolution (MMDE) algorithm is proposed. In proposed algorithm, a heuristic correction method is studied to handle the active power operating constraint, generator ramp-up and ramp-down rate constraints. A marginal analysis correction method is presented to handle the power balance constraint and dynamic adjust load step in the optimization process. Meanwhile, an improved fuzzy-based mechanism is proposed to determine best compromise non-dominated solution. The experimental results demonstrate that MMDE algorithm has better global search ability and is superior to other multi-objective optimization algorithms with continuous 24-h period.