  The China Space Station Telescope (CSST, also known as Xuntian) is a
serviceable two-meter-aperture wide-field telescope operating in the same orbit
as the China Space Station. The CSST plans to survey a sky area of 17,500
deg$^2$ of the medium-to-high Galactic latitude to a depth of 25-26 AB mag in
at least 6 photometric bands over 255-1000 nm. Within such a large sky area,
slitless spectra will also be taken over the same wavelength range as the
imaging survey. Even though the CSST survey is not dedicated to time-domain
studies, it would still detect a large number of transients, such as supernovae
(SNe). In this paper, we simulate photometric SN observations based on a
strawman survey plan using the Sncosmo package. During its 10-year survey, the
CSST is expected to observe about 5 million SNe of various types. With quality
cuts, we obtain a "gold" sample that comprises roughly 7,400 SNe Ia, 2,200 SNe
Ibc, and 6,500 SNe II candidates with correctly classified percentages reaching
91%, 63%, and 93% (formally defined as classification precision), respectively.
The same survey can also trigger alerts for the detection of about 15,500 SNe
Ia (precision 61%) and 2,100 SNe II (precision 49%) candidates at least two
days before the light maxima. Moreover, the near-ultraviolet observations of
the CSST will be able to catch hundreds of shock-cooling events serendipitously
every year. These results demonstrate that the CSST can make a potentially
significant contribution to SN studies.
