  Periodic variables are always of great scientific interest in astrophysics.
Thanks to the rapid advancement of modern large-scale time-domain surveys, the
number of reported variable stars has experienced substantial growth for
several decades, which significantly deepened our comprehension of stellar
structure and binary evolution. The Tsinghua University-Ma Huateng Telescopes
for Survey (TMTS) has started to monitor the LAMOST sky areas since 2020, with
a cadence of 1 minute. During the period from 2020 to 2022, this survey has
resulted in densely sampled light curves for ~ 30,000 variables of the maximum
powers in the Lomb-Scargle periodogram above the 5sigma threshold. In this
paper, we classified 11,638 variable stars into 6 main types using XGBoost and
Random Forest classifiers with accuracies of 98.83% and 98.73%, respectively.
Among them, 5301 (45.55%) variables are newly discovered, primarily consisting
of Delta Scuti stars, demonstrating the capability of TMTS in searching for
short-period variables. We cross-matched the catalogue with Gaia's second Data
Release (DR2) and LAMOST's seventh Data Release (DR7) to obtain important
physical parameters of the variables. We identified 5504 Delta Scuti stars
(including 4876 typical Delta Scuti stars and 628 high-amplitude Delta Scuti
stars), 5899 eclipsing binaries (including EA-, EB- and EW-type) and 226
candidates of RS Canum Venaticorum. Leveraging the metal abundance data
provided by LAMOST and the Galactic latitude, we discovered 8 candidates of SX
Phe stars within the class of "Delta Scuti stars". Moreover, with the help of
Gaia color-magnitude diagram, we identified 9 ZZ ceti stars.
