  Type Ia Supernovae (SNe Ia) are the thermonuclear explosion of a
carbon-oxygen white dwarf (WD) and are well-known as a distance indicator.
However, it is still unclear how WDs increase their mass near the Chandrasekhar
limit and how the thermonuclear runaway happens. The observational clues
associated with these open questions, such as the photometric data within hours
to days since the explosion, are scarce. Thus, an essential way is to discover
SNe Ia at specific epochs with optimal surveys. The 2.5-m Wide Field Survey
Telescope (WFST) is an upcoming survey facility deployed in western China. In
this paper, we assess the detecability of SNe Ia with mock observations of
WFST. Followed by the volumetric rate, we generate a spectral series of SNe Ia
based on a data-based model and introduce the line-of-sight extinction to
calculate the brightness from the observer. By comparing with the detection
limit of WFST, which is affected by the observing conditions, we can count the
number of SNe Ia discovered by mock WFST observations. We expect that WFST can
find more than $3.0\times10^{4}$ pre-maximum SNe Ia within one-year running. In
particular, WFST could discover about 45 bright SNe Ia, 99 early-phase SNe Ia,
or $1.1\times10^{4}$ well-observed SNe Ia with the hypothesized Wide, Deep, or
Medium mode, respectively, suggesting WFST will be an influential facility in
time-domain astronomy.
