  A significant number of double white dwarfs (DWDs) are believed to merge
within the Hubble time due to the gravitational wave (GW) emission during their
inspiraling phase. The outcome of a DWD system is either a type Ia Supernova as
the double-degenerate model, or a massive, long-lasting merger remnant.
Expected multi-messenger signals of these events will help us to distinguish
detailed merging physical processes. In this work, we aim to provide a generic
scenario of DWD merging, investigate the emission of all major messengers, with
a focus on GWs and neutrinos. Our goal is to provide some guidance for current
and future (collaborative) efforts of multi-messenger observations. Throughout
the merging evolution of a DWD system, different messengers (GW, neutrino and
electromagnetic wave) will dominate at different times. In this work, we show
that DWD merger events located at the distance of 1 kpc can indeed produce
detectable signals of GWs and neutrinos. The GW frequency are in 0.3-0.6 Hz
band around 10 days before tidal disruption begin. We estimate that in
optimistic situations, the neutrino number detected by upcoming detectors such
as JUNO and Hyper-Kamiokande can reach O(1) for a DWD merging event at $\sim$ 1
kpc.
