The invention discloses a method for calculating the fatigue stress of a steel bridge deck slab under the combined action of a vehicle load and the temperature. The method includes the following steps: building a steel bridge deck slab-pavement layer integrated fatigue analysis model under the combined action of the vehicle load and the temperature, selecting a single standard fatigue vehicle, loading the integrated fatigue analysis model to the fatigue vehicle, calculating fatigue stress time history curves of welding details under predetermined working conditions, on the basis of the curve, building an analysis model for calculating the fatigue stress time history of the welding details under any working condition, and determining the fatigue stress time history of the welding details under the combined action of the vehicle load and the temperature. The calculation method can achieve simulation of the fatigue stress time history of the steel bridge deck slab during any time period, the simulating result can accurately reflect the change rule of the fatigue stress of the steel bridge deck slab in a real operation state, and the method fills the gap that no appropriate method for calculating the fatigue stress of the steel bridge deck slab under the combined action of the vehicle load and the temperature exists in the prior art.