The effect of hydrogen annealing in each stage of the production of all-copper structure folded waveguide by Ultraviolet-Lithographie Galvanoformung Abformung(UV-LIGA) is studied in detail. The hydrogen annealing step is in two stages, the first stage is the hydrogen treatment of the copper substrate(early stage), and the second stage is the treatment of the substrate and the electroformed layer after realizing the metal structure(later stage). Experiments show that in addition to cleaning the substrate and reducing the internal stress, hydrogen annealing in the early stage also migrates grain boundaries, so that the grain growth tends to be stable at high temperatures, which is conducive to the growth of the electroformed layer with better combination. However, this treatment needs to be advanced before the substrate is polished, otherwise the flatness will deteriorate. In addition to testing whether the all-copper structure can withstand high-temperature welding, hydrogen annealing in the later stage also helps to further remove the photoresist and promotes grain growth of substrate and electroformed layer as a whole at high temperature.