The influence of Ag flake size on the electrical conductivity of silver pastes before and after folding was investigated. The low-temperature curing conductive silver pastes with good electrical conductivity after folding were fabricated using Ag flake with different flake sizes. Then the silver pastes were screen-printed on the polyimide substrate and sintered at 140 °C to form the circuits. The electrical resistivity of the printed circuits was detected by micro-ohmmeter. In order to measure the flexibility of Ag circuits, the variance of electrical resistivity of Ag circuits was detected after they were folded. The surface morphology of the folded Ag circuits was observed by the scanning electron microscopy. The conductive mechanism was analyzed. The results show that the small Ag flakes can act as the bridge between the unconnected flakes and fill the gaps after the circuits are folded, which forms the conductive networks, thereby improving the electrical conductivity after folding.