The invention provides a multi-energy system grid-connected optimization scheduling method and device. The method comprises the steps of S1, constructing an objective function of a multi-energy systemeconomic scheduling model; s2, generating an initial firework population for fireworks according to the output of the unit, calculating the fitness of each firework in the initial firework populationthrough an objective function, and determining the initial firework population as a first firework population; s3, generating a second firework population through an explosion mode based on Tent chaotic mapping according to the fitness of each firework in the first firework population, and performing Gaussian variation on the first firework population to obtain a third firework population; s4, selecting fireworks from the first firework population, the second firework population and the third firework population to form a fourth firework population by taking the fitness as a selection standard; and S5, judging whether an iteration stopping condition is met or not, if yes, taking the optimal fireworks in the fourth fireworks population as the output of the unit, and if not, taking the fourth fireworks population as the first fireworks population and executing the step S3 again.