The Belle experiment, operated on the KEKB accelerator in KEK, had accumulated a data sample with an integrated luminosity of more than 1 ab−1 before the shutdown in 2010. We are preparing upgraded accelerator and detector, called SuperKEKB and Belle-II, to achieve the target luminosity of 8 × 1035cm−1s−1. With the increased luminosity, we expect more beam background which might damage our detector components, hide event signals under noise hits, max out readout bandwidth, etc. Detector shielding is a key to cope with the increased background and protect Belle-II detector. We present how we estimate the impact from each beam background sources at SuperKEKB, such as Touschek-scattering, beam-gas scattering, radiative Bhabha process, etc. We also present our countermeasures to mitigate the beam background, such as tungsten shields installed in the detector to stop shower particles, beam collimators to stop stray beam particles before they reach interaction region, dedicated beam pipe design around interaction point to stop synchrotron radiation, and so on.